Vulnerabilities > CVE-2015-6564 - Permissions, Privileges, and Access Controls vulnerability in Openbsd Openssh
Attack vector
UNKNOWN Attack complexity
UNKNOWN Privileges required
UNKNOWN Confidentiality impact
UNKNOWN Integrity impact
UNKNOWN Availability impact
UNKNOWN Summary
Use-after-free vulnerability in the mm_answer_pam_free_ctx function in monitor.c in sshd in OpenSSH before 7.0 on non-OpenBSD platforms might allow local users to gain privileges by leveraging control of the sshd uid to send an unexpectedly early MONITOR_REQ_PAM_FREE_CTX request.
Vulnerable Configurations
Common Weakness Enumeration (CWE)
Common Attack Pattern Enumeration and Classification (CAPEC)
- Accessing, Modifying or Executing Executable Files An attack of this type exploits a system's configuration that allows an attacker to either directly access an executable file, for example through shell access; or in a possible worst case allows an attacker to upload a file and then execute it. Web servers, ftp servers, and message oriented middleware systems which have many integration points are particularly vulnerable, because both the programmers and the administrators must be in synch regarding the interfaces and the correct privileges for each interface.
- Leverage Executable Code in Non-Executable Files An attack of this type exploits a system's trust in configuration and resource files, when the executable loads the resource (such as an image file or configuration file) the attacker has modified the file to either execute malicious code directly or manipulate the target process (e.g. application server) to execute based on the malicious configuration parameters. Since systems are increasingly interrelated mashing up resources from local and remote sources the possibility of this attack occurring is high. The attack can be directed at a client system, such as causing buffer overrun through loading seemingly benign image files, as in Microsoft Security Bulletin MS04-028 where specially crafted JPEG files could cause a buffer overrun once loaded into the browser. Another example targets clients reading pdf files. In this case the attacker simply appends javascript to the end of a legitimate url for a pdf (http://www.gnucitizen.org/blog/danger-danger-danger/) http://path/to/pdf/file.pdf#whatever_name_you_want=javascript:your_code_here The client assumes that they are reading a pdf, but the attacker has modified the resource and loaded executable javascript into the client's browser process. The attack can also target server processes. The attacker edits the resource or configuration file, for example a web.xml file used to configure security permissions for a J2EE app server, adding role name "public" grants all users with the public role the ability to use the administration functionality. The server trusts its configuration file to be correct, but when they are manipulated, the attacker gains full control.
- Blue Boxing This type of attack against older telephone switches and trunks has been around for decades. A tone is sent by an adversary to impersonate a supervisor signal which has the effect of rerouting or usurping command of the line. While the US infrastructure proper may not contain widespread vulnerabilities to this type of attack, many companies are connected globally through call centers and business process outsourcing. These international systems may be operated in countries which have not upgraded Telco infrastructure and so are vulnerable to Blue boxing. Blue boxing is a result of failure on the part of the system to enforce strong authorization for administrative functions. While the infrastructure is different than standard current applications like web applications, there are historical lessons to be learned to upgrade the access control for administrative functions.
- Restful Privilege Elevation Rest uses standard HTTP (Get, Put, Delete) style permissions methods, but these are not necessarily correlated generally with back end programs. Strict interpretation of HTTP get methods means that these HTTP Get services should not be used to delete information on the server, but there is no access control mechanism to back up this logic. This means that unless the services are properly ACL'd and the application's service implementation are following these guidelines then an HTTP request can easily execute a delete or update on the server side. The attacker identifies a HTTP Get URL such as http://victimsite/updateOrder, which calls out to a program to update orders on a database or other resource. The URL is not idempotent so the request can be submitted multiple times by the attacker, additionally, the attacker may be able to exploit the URL published as a Get method that actually performs updates (instead of merely retrieving data). This may result in malicious or inadvertent altering of data on the server.
- Target Programs with Elevated Privileges This attack targets programs running with elevated privileges. The attacker would try to leverage a bug in the running program and get arbitrary code to execute with elevated privileges. For instance an attacker would look for programs that write to the system directories or registry keys (such as HKLM, which stores a number of critical Windows environment variables). These programs are typically running with elevated privileges and have usually not been designed with security in mind. Such programs are excellent exploit targets because they yield lots of power when they break. The malicious user try to execute its code at the same level as a privileged system call.
Nessus
NASL family AIX Local Security Checks NASL id AIX_OPENSSH_ADVISORY6.NASL description The remote AIX host has a version of OpenSSH installed that is affected by the following vulnerabilities : - A flaw exists in the monitor component when handling extraneous username data in MONITOR_REQ_PAM_INIT_CTX requests. A local attacker can exploit this issue to conduct an impersonation attack, by sending a crafted MONITOR_REQ_PWNAM request that leverages any SSH login access with control of the sshd UID. (CVE-2015-6563) - A use-after-free error exists in function mm_answer_pam_free_ctx() in the file monitor.c when handling MONITOR_REQ_PAM_FREE_CTX requests. A local attacker can exploit this to gain elevated privileges, by leveraging control of the sshd UID to send an unexpectedly early MONITOR_REQ_PAM_FREE_CTX request. (CVE-2015-6564) last seen 2020-06-01 modified 2020-06-02 plugin id 86656 published 2015-10-29 reporter This script is Copyright (C) 2015-2018 Tenable Network Security, Inc. source https://www.tenable.com/plugins/nessus/86656 title AIX OpenSSH Advisory : openssh_advisory6.asc code # # (C) Tenable Network Security, Inc. # include("compat.inc"); if (description) { script_id(86656); script_version("1.9"); script_cvs_date("Date: 2018/07/17 12:00:06"); script_cve_id("CVE-2015-6563", "CVE-2015-6564"); script_bugtraq_id(76317); script_name(english:"AIX OpenSSH Advisory : openssh_advisory6.asc"); script_summary(english:"Checks the version of the OpenSSH packages and iFixes."); script_set_attribute(attribute:"synopsis", value: "The remote AIX host has a version of OpenSSH installed that is affected by multiple vulnerabilities."); script_set_attribute(attribute:"description", value: "The remote AIX host has a version of OpenSSH installed that is affected by the following vulnerabilities : - A flaw exists in the monitor component when handling extraneous username data in MONITOR_REQ_PAM_INIT_CTX requests. A local attacker can exploit this issue to conduct an impersonation attack, by sending a crafted MONITOR_REQ_PWNAM request that leverages any SSH login access with control of the sshd UID. (CVE-2015-6563) - A use-after-free error exists in function mm_answer_pam_free_ctx() in the file monitor.c when handling MONITOR_REQ_PAM_FREE_CTX requests. A local attacker can exploit this to gain elevated privileges, by leveraging control of the sshd UID to send an unexpectedly early MONITOR_REQ_PAM_FREE_CTX request. (CVE-2015-6564)"); script_set_attribute(attribute:"see_also", value:"http://aix.software.ibm.com/aix/efixes/security/openssh_advisory6.asc"); script_set_attribute(attribute:"see_also", value:"https://www-01.ibm.com/marketing/iwm/iwm/web/preLogin.do?source=aixbp"); script_set_attribute(attribute:"solution", value: "A fix is available and can be downloaded from the AIX website."); script_set_cvss_base_vector("CVSS2#AV:L/AC:M/Au:N/C:C/I:C/A:C"); script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C"); script_set_attribute(attribute:"vuln_publication_date", value:"2015/08/11"); script_set_attribute(attribute:"patch_publication_date", value:"2015/10/21"); script_set_attribute(attribute:"plugin_publication_date", value:"2015/10/29"); script_set_attribute(attribute:"plugin_type", value:"local"); script_set_attribute(attribute:"cpe", value:"cpe:/o:ibm:aix:5.3"); script_set_attribute(attribute:"cpe", value:"cpe:/o:ibm:aix:6.1"); script_set_attribute(attribute:"cpe", value:"cpe:/o:ibm:aix:7.1"); script_set_attribute(attribute:"cpe", value:"cpe:/a:openbsd:openssh"); script_end_attributes(); script_category(ACT_GATHER_INFO); script_family(english:"AIX Local Security Checks"); script_copyright(english:"This script is Copyright (C) 2015-2018 Tenable Network Security, Inc."); script_dependencies("ssh_get_info.nasl"); script_require_keys("Host/AIX/lslpp", "Host/local_checks_enabled", "Host/AIX/version"); exit(0); } include("aix.inc"); include("audit.inc"); include("global_settings.inc"); include("misc_func.inc"); if ( ! get_kb_item("Host/local_checks_enabled") ) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED); oslevel = get_kb_item("Host/AIX/version"); if (isnull(oslevel)) audit(AUDIT_UNKNOWN_APP_VER, "AIX"); if ( oslevel != "AIX-5.3" && oslevel != "AIX-6.1" && oslevel != "AIX-7.1" ) { oslevel = ereg_replace(string:oslevel, pattern:"-", replace:" "); audit(AUDIT_OS_NOT, "AIX 5.3 / 6.1 / 7.1", oslevel); } if ( ! get_kb_item("Host/AIX/lslpp") ) audit(AUDIT_PACKAGE_LIST_MISSING); if ( get_kb_item("Host/AIX/emgr_failure" ) ) exit(0, "This AIX package check is disabled because : "+get_kb_item("Host/AIX/emgr_failure") ); flag = 0; ifixes_6110 = "(6110_ifix|IV80743m9b|IV84698m9b)"; ifixes_6201 = "(6201_ifix|IV80743m9a|IV84698m9a)"; if (aix_check_ifix(release:"5.3", patch:ifixes_6110, package:"openssh.base.client", minfilesetver:"4.0.0.5200", maxfilesetver:"6.0.0.6110") < 0) flag++; if (aix_check_ifix(release:"5.3", patch:ifixes_6201, package:"openssh.base.client", minfilesetver:"6.0.0.6200", maxfilesetver:"6.0.0.6201") < 0) flag++; if (aix_check_ifix(release:"6.1", patch:ifixes_6110, package:"openssh.base.client", minfilesetver:"4.0.0.5200", maxfilesetver:"6.0.0.6110") < 0) flag++; if (aix_check_ifix(release:"6.1", patch:ifixes_6201, package:"openssh.base.client", minfilesetver:"6.0.0.6200", maxfilesetver:"6.0.0.6201") < 0) flag++; if (aix_check_ifix(release:"7.1", patch:ifixes_6110, package:"openssh.base.client", minfilesetver:"4.0.0.5200", maxfilesetver:"6.0.0.6110") < 0) flag++; if (aix_check_ifix(release:"7.1", patch:ifixes_6201, package:"openssh.base.client", minfilesetver:"6.0.0.6200", maxfilesetver:"6.0.0.6201") < 0) flag++; if (aix_check_ifix(release:"5.3", patch:ifixes_6110, package:"openssh.base.server", minfilesetver:"4.0.0.5200", maxfilesetver:"6.0.0.6110") < 0) flag++; if (aix_check_ifix(release:"5.3", patch:ifixes_6201, package:"openssh.base.server", minfilesetver:"6.0.0.6200", maxfilesetver:"6.0.0.6201") < 0) flag++; if (aix_check_ifix(release:"6.1", patch:ifixes_6110, package:"openssh.base.server", minfilesetver:"4.0.0.5200", maxfilesetver:"6.0.0.6110") < 0) flag++; if (aix_check_ifix(release:"6.1", patch:ifixes_6201, package:"openssh.base.server", minfilesetver:"6.0.0.6200", maxfilesetver:"6.0.0.6201") < 0) flag++; if (aix_check_ifix(release:"7.1", patch:ifixes_6110, package:"openssh.base.server", minfilesetver:"4.0.0.5200", maxfilesetver:"6.0.0.6110") < 0) flag++; if (aix_check_ifix(release:"7.1", patch:ifixes_6201, package:"openssh.base.server", minfilesetver:"6.0.0.6200", maxfilesetver:"6.0.0.6201") < 0) flag++; if (flag) { aix_report_extra = ereg_replace(string:aix_report_get(), pattern:"[()]", replace:""); aix_report_extra = ereg_replace(string:aix_report_extra, pattern:"[|]", replace:" or "); security_report_v4( port : 0, severity : SECURITY_WARNING, extra : aix_report_extra ); } else { tested = aix_pkg_tests_get(); if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested); else audit(AUDIT_PACKAGE_NOT_INSTALLED, "openssh.base.client / openssh.base.server"); }NASL family Scientific Linux Local Security Checks NASL id SL_20160510_OPENSSH_ON_SL6_X.NASL description Security Fix(es) : - It was found that the OpenSSH client did not properly enforce the ForwardX11Timeout setting. A malicious or compromised remote X application could possibly use this flaw to establish a trusted connection to the local X server, even if only untrusted X11 forwarding was requested. (CVE-2015-5352) - A flaw was found in the way OpenSSH handled PAM authentication when using privilege separation. An attacker with valid credentials on the system and able to fully compromise a non-privileged pre-authentication process using a different flaw could use this flaw to authenticate as other users. (CVE-2015-6563) - A use-after-free flaw was found in OpenSSH. An attacker able to fully compromise a non-privileged pre-authentication process using a different flaw could possibly cause sshd to crash or execute arbitrary code with root privileges. (CVE-2015-6564) - An access flaw was discovered in OpenSSH; the OpenSSH client did not correctly handle failures to generate authentication cookies for untrusted X11 forwarding. A malicious or compromised remote X application could possibly use this flaw to establish a trusted connection to the local X server, even if only untrusted X11 forwarding was requested. (CVE-2016-1908) last seen 2020-03-18 modified 2016-06-09 plugin id 91540 published 2016-06-09 reporter This script is Copyright (C) 2016-2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/91540 title Scientific Linux Security Update : openssh on SL6.x i386/x86_64 (20160510) NASL family Misc. NASL id OPENSSH_70.NASL description According to its banner, the version of OpenSSH running on the remote host is prior to 7.0. It is, therefore, affected by the following vulnerabilities : - A security bypass vulnerability exists in the kbdint_next_device() function in file auth2-chall.c that allows the circumvention of MaxAuthTries during keyboard-interactive authentication. A remote attacker can exploit this issue to force the same authentication method to be tried thousands of times in a single pass by using a crafted keyboard-interactive last seen 2020-06-01 modified 2020-06-02 plugin id 85382 published 2015-08-13 reporter This script is Copyright (C) 2015-2018 Tenable Network Security, Inc. source https://www.tenable.com/plugins/nessus/85382 title OpenSSH < 7.0 Multiple Vulnerabilities NASL family FreeBSD Local Security Checks NASL id FREEBSD_PKG_2920C449485011E5825FC80AA9043978.NASL description OpenSSH 6.8 and 6.9 incorrectly set TTYs to be world-writable. Local attackers may be able to write arbitrary messages to logged-in users, including terminal escape sequences. Reported by Nikolay Edigaryev. Fixed a privilege separation weakness related to PAM support. Attackers who could successfully compromise the pre-authentication process for remote code execution and who had valid credentials on the host could impersonate other users. Fixed a use-after-free bug related to PAM support that was reachable by attackers who could compromise the pre-authentication process for remote code execution. last seen 2020-06-01 modified 2020-06-02 plugin id 85594 published 2015-08-24 reporter This script is Copyright (C) 2015-2018 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/85594 title FreeBSD : OpenSSH -- PAM vulnerabilities (2920c449-4850-11e5-825f-c80aa9043978) NASL family Oracle Linux Local Security Checks NASL id ORACLELINUX_ELSA-2015-2088.NASL description From Red Hat Security Advisory 2015:2088 : Updated openssh packages that fix multiple security issues, several bugs, and add various enhancements are now available for Red Hat Enterprise Linux 7. Red Hat Product Security has rated this update as having Moderate security impact. Common Vulnerability Scoring System (CVSS) base scores, which give detailed severity ratings, are available for each vulnerability from the CVE links in the References section. OpenSSH is OpenBSD last seen 2020-06-01 modified 2020-06-02 plugin id 87019 published 2015-11-24 reporter This script is Copyright (C) 2015-2019 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/87019 title Oracle Linux 7 : openssh (ELSA-2015-2088) NASL family SuSE Local Security Checks NASL id SUSE_SU-2015-1547-2.NASL description openssh was updated to fix several security issues and bugs. These security issues were fixed : - CVE-2015-5352: The x11_open_helper function in channels.c in ssh in OpenSSH when ForwardX11Trusted mode is not used, lacked a check of the refusal deadline for X connections, which made it easier for remote attackers to bypass intended access restrictions via a connection outside of the permitted time window (bsc#936695). - CVE-2015-5600: The kbdint_next_device function in auth2-chall.c in sshd in OpenSSH did not properly restrict the processing of keyboard-interactive devices within a single connection, which made it easier for remote attackers to conduct brute-force attacks or cause a denial of service (CPU consumption) via a long and duplicative list in the ssh -oKbdInteractiveDevices option, as demonstrated by a modified client that provides a different password for each pam element on this list (bsc#938746). - CVE-2015-4000: Removed and disabled weak DH groups to address LOGJAM (bsc#932483). - Hardening patch to fix sftp RCE (bsc#903649). - CVE-2015-6563: The monitor component in sshd in OpenSSH accepted extraneous username data in MONITOR_REQ_PAM_INIT_CTX requests, which allowed local users to conduct impersonation attacks by leveraging any SSH login access in conjunction with control of the sshd uid to send a crafted MONITOR_REQ_PWNAM request, related to monitor.c and monitor_wrap.c. - CVE-2015-6564: Use-after-free vulnerability in the mm_answer_pam_free_ctx function in monitor.c in sshd in OpenSSH might have allowed local users to gain privileges by leveraging control of the sshd uid to send an unexpectedly early MONITOR_REQ_PAM_FREE_CTX request. The update package also includes non-security fixes. See advisory for details. Note that Tenable Network Security has extracted the preceding description block directly from the SUSE security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues. last seen 2020-06-01 modified 2020-06-02 plugin id 85941 published 2015-09-15 reporter This script is Copyright (C) 2015-2019 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/85941 title SUSE SLED11 Security Update : openssh (SUSE-SU-2015:1547-2) (Logjam) NASL family SuSE Local Security Checks NASL id SUSE_SU-2015-1581-1.NASL description openssh was updated to fix several security issues and bugs. These security issues were fixed : - CVE-2015-5352: The x11_open_helper function in channels.c in ssh in OpenSSH when ForwardX11Trusted mode is not used, lacked a check of the refusal deadline for X connections, which made it easier for remote attackers to bypass intended access restrictions via a connection outside of the permitted time window (bsc#936695). - CVE-2015-5600: The kbdint_next_device function in auth2-chall.c in sshd in OpenSSH did not properly restrict the processing of keyboard-interactive devices within a single connection, which made it easier for remote attackers to conduct brute-force attacks or cause a denial of service (CPU consumption) via a long and duplicative list in the ssh -oKbdInteractiveDevices option, as demonstrated by a modified client that provides a different password for each pam element on this list (bsc#938746). - CVE-2015-4000: Removed and disabled weak DH groups to address LOGJAM (bsc#932483). - Hardening patch to fix sftp RCE (bsc#903649). - CVE-2015-6563: The monitor component in sshd in OpenSSH accepted extraneous username data in MONITOR_REQ_PAM_INIT_CTX requests, which allowed local users to conduct impersonation attacks by leveraging any SSH login access in conjunction with control of the sshd uid to send a crafted MONITOR_REQ_PWNAM request, related to monitor.c and monitor_wrap.c. - CVE-2015-6564: Use-after-free vulnerability in the mm_answer_pam_free_ctx function in monitor.c in sshd in OpenSSH might have allowed local users to gain privileges by leveraging control of the sshd uid to send an unexpectedly early MONITOR_REQ_PAM_FREE_CTX request. The update package also includes non-security fixes. See advisory for details. Note that Tenable Network Security has extracted the preceding description block directly from the SUSE security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues. last seen 2020-06-01 modified 2020-06-02 plugin id 86057 published 2015-09-22 reporter This script is Copyright (C) 2015-2019 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/86057 title SUSE SLED11 / SLES11 Security Update : openssh (SUSE-SU-2015:1581-1) (Logjam) NASL family CentOS Local Security Checks NASL id CENTOS_RHSA-2015-2088.NASL description Updated openssh packages that fix multiple security issues, several bugs, and add various enhancements are now available for Red Hat Enterprise Linux 7. Red Hat Product Security has rated this update as having Moderate security impact. Common Vulnerability Scoring System (CVSS) base scores, which give detailed severity ratings, are available for each vulnerability from the CVE links in the References section. OpenSSH is OpenBSD last seen 2020-06-01 modified 2020-06-02 plugin id 87128 published 2015-12-02 reporter This script is Copyright (C) 2015-2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/87128 title CentOS 7 : openssh (CESA-2015:2088) NASL family Red Hat Local Security Checks NASL id REDHAT-RHSA-2016-0741.NASL description An update for openssh is now available for Red Hat Enterprise Linux 6. Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section. OpenSSH is an SSH protocol implementation supported by a number of Linux, UNIX, and similar operating systems. It includes the core files necessary for both the OpenSSH client and server. Security Fix(es) : * It was found that the OpenSSH client did not properly enforce the ForwardX11Timeout setting. A malicious or compromised remote X application could possibly use this flaw to establish a trusted connection to the local X server, even if only untrusted X11 forwarding was requested. (CVE-2015-5352) * A flaw was found in the way OpenSSH handled PAM authentication when using privilege separation. An attacker with valid credentials on the system and able to fully compromise a non-privileged pre-authentication process using a different flaw could use this flaw to authenticate as other users. (CVE-2015-6563) * A use-after-free flaw was found in OpenSSH. An attacker able to fully compromise a non-privileged pre-authentication process using a different flaw could possibly cause sshd to crash or execute arbitrary code with root privileges. (CVE-2015-6564) * An access flaw was discovered in OpenSSH; the OpenSSH client did not correctly handle failures to generate authentication cookies for untrusted X11 forwarding. A malicious or compromised remote X application could possibly use this flaw to establish a trusted connection to the local X server, even if only untrusted X11 forwarding was requested. (CVE-2016-1908) For detailed information on changes in this release, see the Red Hat Enterprise Linux 6.8 Release Notes and Red Hat Enterprise Linux 6.8 Technical Notes linked from the References section. last seen 2020-06-01 modified 2020-06-02 plugin id 91073 published 2016-05-12 reporter This script is Copyright (C) 2016-2019 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/91073 title RHEL 6 : openssh (RHSA-2016:0741) NASL family Firewalls NASL id PFSENSE_SA-15_08.NASL description According to its self-reported version number, the remote pfSense install is prior to 2.2.5. It is, therefore, affected by multiple vulnerabilities as stated in the referenced vendor advisories. last seen 2020-06-01 modified 2020-06-02 plugin id 106497 published 2018-01-31 reporter This script is Copyright (C) 2018 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/106497 title pfSense < 2.2.5 Multiple Vulnerabilities (SA-15_08) NASL family Fedora Local Security Checks NASL id FEDORA_2015-13469.NASL description This update provides fixes for vulnerabilities published with openssh-7.0 Security fix for CVE-2015-5600 Note that Tenable Network Security has extracted the preceding description block directly from the Fedora security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues. last seen 2020-06-05 modified 2015-08-28 plugin id 85668 published 2015-08-28 reporter This script is Copyright (C) 2015-2020 Tenable Network Security, Inc. source https://www.tenable.com/plugins/nessus/85668 title Fedora 21 : openssh-6.6.1p1-16.fc21 (2015-13469) NASL family F5 Networks Local Security Checks NASL id F5_BIGIP_SOL17263.NASL description CVE-2015-6563 The monitor component in sshd in OpenSSH before 7.0 on non-OpenBSD platforms accepts extraneous username data in MONITOR_REQ_PAM_INIT_CTX requests, which allows local users to conduct impersonation attacks by leveraging any SSH login access in conjunction with control of the sshd uid to send a crafted MONITOR_REQ_PWNAM request, related to monitor.c and monitor_wrap.c. CVE-2015-6564 Use-after-free vulnerability in the mm_answer_pam_free_ctx function in monitor.c in sshd in OpenSSH before 7.0 on non-OpenBSD platforms might allow local users to gain privileges by leveraging control of the sshd uid to send an unexpectedly early MONITOR_REQ_PAM_FREE_CTX request. last seen 2020-06-01 modified 2020-06-02 plugin id 91432 published 2016-06-02 reporter This script is Copyright (C) 2016-2019 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/91432 title F5 Networks BIG-IP : OpenSSH vulnerabilities (K17263) NASL family Scientific Linux Local Security Checks NASL id SL_20151119_OPENSSH_ON_SL7_X.NASL description A flaw was found in the way OpenSSH handled PAM authentication when using privilege separation. An attacker with valid credentials on the system and able to fully compromise a non-privileged pre-authentication process using a different flaw could use this flaw to authenticate as other users. (CVE-2015-6563) A use-after-free flaw was found in OpenSSH. An attacker able to fully compromise a non-privileged pre-authentication process using a different flaw could possibly cause sshd to crash or execute arbitrary code with root privileges. (CVE-2015-6564) It was discovered that the OpenSSH sshd daemon did not check the list of keyboard-interactive authentication methods for duplicates. A remote attacker could use this flaw to bypass the MaxAuthTries limit, making it easier to perform password guessing attacks. (CVE-2015-5600) It was found that the OpenSSH ssh-agent, a program to hold private keys used for public key authentication, was vulnerable to password guessing attacks. An attacker able to connect to the agent could use this flaw to conduct a brute-force attack to unlock keys in the ssh-agent. This update fixes the following bugs : - Previously, the sshd_config(5) man page was misleading and could thus confuse the user. This update improves the man page text to clearly describe the AllowGroups feature. - The limit for the function for restricting the number of files listed using the wildcard character (*) that prevents the Denial of Service (DoS) for both server and client was previously set too low. Consequently, the user reaching the limit was prevented from listing a directory with a large number of files over Secure File Transfer Protocol (SFTP). This update increases the aforementioned limit, thus fixing this bug. - When the ForceCommand option with a pseudoterminal was used and the MaxSession option was set to last seen 2020-03-18 modified 2015-12-22 plugin id 87567 published 2015-12-22 reporter This script is Copyright (C) 2015-2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/87567 title Scientific Linux Security Update : openssh on SL7.x x86_64 (20151119) NASL family Amazon Linux Local Security Checks NASL id ALA_ALAS-2015-625.NASL description A flaw was found in the way OpenSSH handled PAM authentication when using privilege separation. An attacker with valid credentials on the system and able to fully compromise a non-privileged pre-authentication process using a different flaw could use this flaw to authenticate as other users. It was discovered that the OpenSSH sshd daemon did not check the list of keyboard-interactive authentication methods for duplicates. A remote attacker could use this flaw to bypass the MaxAuthTries limit, making it easier to perform password guessing attacks. A use-after-free flaw was found in OpenSSH. An attacker able to fully compromise a non-privileged pre-authentication process using a different flaw could possibly cause sshd to crash or execute arbitrary code with root privileges. last seen 2020-06-01 modified 2020-06-02 plugin id 87351 published 2015-12-15 reporter This script is Copyright (C) 2015-2018 Tenable Network Security, Inc. source https://www.tenable.com/plugins/nessus/87351 title Amazon Linux AMI : openssh (ALAS-2015-625) NASL family Red Hat Local Security Checks NASL id REDHAT-RHSA-2015-2088.NASL description Updated openssh packages that fix multiple security issues, several bugs, and add various enhancements are now available for Red Hat Enterprise Linux 7. Red Hat Product Security has rated this update as having Moderate security impact. Common Vulnerability Scoring System (CVSS) base scores, which give detailed severity ratings, are available for each vulnerability from the CVE links in the References section. OpenSSH is OpenBSD last seen 2020-06-01 modified 2020-06-02 plugin id 86967 published 2015-11-20 reporter This script is Copyright (C) 2015-2019 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/86967 title RHEL 7 : openssh (RHSA-2015:2088) NASL family CentOS Local Security Checks NASL id CENTOS_RHSA-2016-0741.NASL description An update for openssh is now available for Red Hat Enterprise Linux 6. Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section. OpenSSH is an SSH protocol implementation supported by a number of Linux, UNIX, and similar operating systems. It includes the core files necessary for both the OpenSSH client and server. Security Fix(es) : * It was found that the OpenSSH client did not properly enforce the ForwardX11Timeout setting. A malicious or compromised remote X application could possibly use this flaw to establish a trusted connection to the local X server, even if only untrusted X11 forwarding was requested. (CVE-2015-5352) * A flaw was found in the way OpenSSH handled PAM authentication when using privilege separation. An attacker with valid credentials on the system and able to fully compromise a non-privileged pre-authentication process using a different flaw could use this flaw to authenticate as other users. (CVE-2015-6563) * A use-after-free flaw was found in OpenSSH. An attacker able to fully compromise a non-privileged pre-authentication process using a different flaw could possibly cause sshd to crash or execute arbitrary code with root privileges. (CVE-2015-6564) * An access flaw was discovered in OpenSSH; the OpenSSH client did not correctly handle failures to generate authentication cookies for untrusted X11 forwarding. A malicious or compromised remote X application could possibly use this flaw to establish a trusted connection to the local X server, even if only untrusted X11 forwarding was requested. (CVE-2016-1908) For detailed information on changes in this release, see the Red Hat Enterprise Linux 6.8 Release Notes and Red Hat Enterprise Linux 6.8 Technical Notes linked from the References section. last seen 2020-06-01 modified 2020-06-02 plugin id 91166 published 2016-05-17 reporter This script is Copyright (C) 2016-2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/91166 title CentOS 6 : openssh (CESA-2016:0741) NASL family SuSE Local Security Checks NASL id SUSE_SU-2015-1544-1.NASL description openssh was updated to fix several security issues. These security issues were fixed : - CVE-2015-5352: The x11_open_helper function in channels.c in ssh in OpenSSH when ForwardX11Trusted mode is not used, lacked a check of the refusal deadline for X connections, which made it easier for remote attackers to bypass intended access restrictions via a connection outside of the permitted time window (bsc#936695). - CVE-2015-5600: The kbdint_next_device function in auth2-chall.c in sshd in OpenSSH did not properly restrict the processing of keyboard-interactive devices within a single connection, which made it easier for remote attackers to conduct brute-force attacks or cause a denial of service (CPU consumption) via a long and duplicative list in the ssh -oKbdInteractiveDevices option, as demonstrated by a modified client that provides a different password for each pam element on this list (bsc#938746). - CVE-2015-4000: Removed and disabled weak DH groups to address LOGJAM (bsc#932483). - Hardening patch to fix sftp RCE (bsc#903649). - CVE-2015-6563: The monitor component in sshd in OpenSSH accepted extraneous username data in MONITOR_REQ_PAM_INIT_CTX requests, which allowed local users to conduct impersonation attacks by leveraging any SSH login access in conjunction with control of the sshd uid to send a crafted MONITOR_REQ_PWNAM request, related to monitor.c and monitor_wrap.c. (bsc#943010) - CVE-2015-6564: Use-after-free vulnerability in the mm_answer_pam_free_ctx function in monitor.c in sshd in OpenSSH might have allowed local users to gain privileges by leveraging control of the sshd uid to send an unexpectedly early MONITOR_REQ_PAM_FREE_CTX request. (bsc#943006) Also use %restart_on_update in the trigger script. Note that Tenable Network Security has extracted the preceding description block directly from the SUSE security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues. last seen 2020-06-01 modified 2020-06-02 plugin id 85928 published 2015-09-14 reporter This script is Copyright (C) 2015-2019 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/85928 title SUSE SLED12 / SLES12 Security Update : openssh (SUSE-SU-2015:1544-1) (Logjam) NASL family SuSE Local Security Checks NASL id SUSE_SU-2015-1695-1.NASL description OpenSSH was updated to fix several security issues and bugs. Please note that due to a bug in the previous shipped openssh version, sshd might not correctly restart. Please verify that the ssh daemon is running after installing this update. These security issues were fixed : - CVE-2015-5352: The x11_open_helper function, when ForwardX11Trusted mode is not used, lacked a check of the refusal deadline for X connections, which made it easier for remote attackers to bypass intended access restrictions via a connection outside of the permitted time window. (bsc#936695) - CVE-2015-5600: The kbdint_next_device function in auth2-chall.c in sshd did not properly restrict the processing of keyboard-interactive devices within a single connection, which made it easier for remote attackers to conduct brute-force attacks or cause a denial of service (CPU consumption) via a long and duplicative list in the ssh -oKbdInteractiveDevices option, as demonstrated by a modified client that provides a different password for each pam element on this list. (bsc#938746) - CVE-2015-4000: Removed and disabled weak DH groups to address LOGJAM. (bsc#932483) - Hardening patch to fix sftp RCE. (bsc#903649) - CVE-2015-6563: The monitor component in sshd accepted extraneous username data in MONITOR_REQ_PAM_INIT_CTX requests, which allowed local users to conduct impersonation attacks by leveraging any SSH login access in conjunction with control of the sshd uid to send a crafted MONITOR_REQ_PWNAM request, related to monitor.c and monitor_wrap.c. - CVE-2015-6564: Use-after-free vulnerability in the mm_answer_pam_free_ctx function in monitor.c in sshd might have allowed local users to gain privileges by leveraging control of the sshd uid to send an unexpectedly early MONITOR_REQ_PAM_FREE_CTX request. Additional a bug was fixed that could lead to openssh not working in chroot (bsc#947458). Note that Tenable Network Security has extracted the preceding description block directly from the SUSE security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues. last seen 2020-06-01 modified 2020-06-02 plugin id 86339 published 2015-10-12 reporter This script is Copyright (C) 2015-2019 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/86339 title SUSE SLED11 / SLES11 Security Update : openssh (SUSE-SU-2015:1695-1) (Logjam) NASL family Oracle Linux Local Security Checks NASL id ORACLELINUX_ELSA-2016-0741.NASL description From Red Hat Security Advisory 2016:0741 : An update for openssh is now available for Red Hat Enterprise Linux 6. Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section. OpenSSH is an SSH protocol implementation supported by a number of Linux, UNIX, and similar operating systems. It includes the core files necessary for both the OpenSSH client and server. Security Fix(es) : * It was found that the OpenSSH client did not properly enforce the ForwardX11Timeout setting. A malicious or compromised remote X application could possibly use this flaw to establish a trusted connection to the local X server, even if only untrusted X11 forwarding was requested. (CVE-2015-5352) * A flaw was found in the way OpenSSH handled PAM authentication when using privilege separation. An attacker with valid credentials on the system and able to fully compromise a non-privileged pre-authentication process using a different flaw could use this flaw to authenticate as other users. (CVE-2015-6563) * A use-after-free flaw was found in OpenSSH. An attacker able to fully compromise a non-privileged pre-authentication process using a different flaw could possibly cause sshd to crash or execute arbitrary code with root privileges. (CVE-2015-6564) * An access flaw was discovered in OpenSSH; the OpenSSH client did not correctly handle failures to generate authentication cookies for untrusted X11 forwarding. A malicious or compromised remote X application could possibly use this flaw to establish a trusted connection to the local X server, even if only untrusted X11 forwarding was requested. (CVE-2016-1908) For detailed information on changes in this release, see the Red Hat Enterprise Linux 6.8 Release Notes and Red Hat Enterprise Linux 6.8 Technical Notes linked from the References section. last seen 2020-06-01 modified 2020-06-02 plugin id 91148 published 2016-05-16 reporter This script is Copyright (C) 2016-2019 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/91148 title Oracle Linux 6 : openssh (ELSA-2016-0741) NASL family Gentoo Local Security Checks NASL id GENTOO_GLSA-201512-04.NASL description The remote host is affected by the vulnerability described in GLSA-201512-04 (OpenSSH: Multiple vulnerabilities) Multiple vulnerabilities have been discovered in OpenSSH. Please review the CVE identifiers referenced below for details. Impact : Workaround : There is no known workaround at this time. last seen 2020-06-01 modified 2020-06-02 plugin id 87545 published 2015-12-22 reporter This script is Copyright (C) 2015 Tenable Network Security, Inc. source https://www.tenable.com/plugins/nessus/87545 title GLSA-201512-04 : OpenSSH: Multiple vulnerabilities NASL family SuSE Local Security Checks NASL id SUSE_SU-2015-1547-1.NASL description openssh was updated to fix several security issues and bugs. These security issues were fixed : - CVE-2015-5352: The x11_open_helper function in channels.c in ssh in OpenSSH when ForwardX11Trusted mode is not used, lacked a check of the refusal deadline for X connections, which made it easier for remote attackers to bypass intended access restrictions via a connection outside of the permitted time window (bsc#936695). - CVE-2015-5600: The kbdint_next_device function in auth2-chall.c in sshd in OpenSSH did not properly restrict the processing of keyboard-interactive devices within a single connection, which made it easier for remote attackers to conduct brute-force attacks or cause a denial of service (CPU consumption) via a long and duplicative list in the ssh -oKbdInteractiveDevices option, as demonstrated by a modified client that provides a different password for each pam element on this list (bsc#938746). - CVE-2015-4000: Removed and disabled weak DH groups to address LOGJAM (bsc#932483). - Hardening patch to fix sftp RCE (bsc#903649). - CVE-2015-6563: The monitor component in sshd in OpenSSH accepted extraneous username data in MONITOR_REQ_PAM_INIT_CTX requests, which allowed local users to conduct impersonation attacks by leveraging any SSH login access in conjunction with control of the sshd uid to send a crafted MONITOR_REQ_PWNAM request, related to monitor.c and monitor_wrap.c. - CVE-2015-6564: Use-after-free vulnerability in the mm_answer_pam_free_ctx function in monitor.c in sshd in OpenSSH might have allowed local users to gain privileges by leveraging control of the sshd uid to send an unexpectedly early MONITOR_REQ_PAM_FREE_CTX request. The update package also includes non-security fixes. See advisory for details. Note that Tenable Network Security has extracted the preceding description block directly from the SUSE security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues. last seen 2020-06-01 modified 2020-06-02 plugin id 85929 published 2015-09-14 reporter This script is Copyright (C) 2015-2019 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/85929 title SUSE SLES11 Security Update : openssh (SUSE-SU-2015:1547-1) (Logjam) NASL family Junos Local Security Checks NASL id JUNIPER_JSA10940.NASL description The version of Junos OS installed on the remote host is prior to 12.3X48-D55, 12.3R12-S13, 15.1X49-D100, 15.1F6-S12, 16.1R3-S4, 16.2R1-S4, 17.1R1-S2, or 17.2R1. It is, therefore, affected by a vulnerability as referenced in the JSA10940 advisory. Note that Nessus has not tested for this issue but has instead relied only on the application last seen 2020-06-01 modified 2020-06-02 plugin id 130514 published 2019-11-06 reporter This script is Copyright (C) 2019 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/130514 title Juniper JSA10940 NASL family Amazon Linux Local Security Checks NASL id ALA_ALAS-2015-592.NASL description The monitor component in sshd in OpenSSH before 7.0 on non-OpenBSD platforms accepts extraneous username data in MONITOR_REQ_PAM_INIT_CTX requests, which allows local users to conduct impersonation attacks by leveraging any SSH login access in conjunction with control of the sshd uid to send a crafted MONITOR_REQ_PWNAM request, related to monitor.c and monitor_wrap.c. (CVE-2015-6563) Use-after-free vulnerability in the mm_answer_pam_free_ctx function in monitor.c in sshd in OpenSSH before 7.0 on non-OpenBSD platforms might allow local users to gain privileges by leveraging control of the sshd uid to send an unexpectedly early MONITOR_REQ_PAM_FREE_CTX request. (CVE-2015-6564) last seen 2020-06-01 modified 2020-06-02 plugin id 85750 published 2015-09-03 reporter This script is Copyright (C) 2015-2018 Tenable Network Security, Inc. source https://www.tenable.com/plugins/nessus/85750 title Amazon Linux AMI : openssh (ALAS-2015-592)
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References
- https://github.com/openssh/openssh-portable/commit/5e75f5198769056089fb06c4d738ab0e5abc66f7
- http://seclists.org/fulldisclosure/2015/Aug/54
- http://www.openwall.com/lists/oss-security/2015/08/22/1
- http://www.openssh.com/txt/release-7.0
- http://www.oracle.com/technetwork/topics/security/linuxbulletinapr2016-2952096.html
- http://www.oracle.com/technetwork/topics/security/linuxbulletinoct2015-2719645.html
- http://www.oracle.com/technetwork/topics/security/bulletinjan2016-2867206.html
- http://www.securityfocus.com/bid/76317
- https://security.gentoo.org/glsa/201512-04
- https://kc.mcafee.com/corporate/index?page=content&id=SB10136
- http://lists.opensuse.org/opensuse-security-announce/2015-09/msg00017.html
- http://lists.fedoraproject.org/pipermail/package-announce/2015-August/165170.html
- http://rhn.redhat.com/errata/RHSA-2016-0741.html
- https://lists.debian.org/debian-lts-announce/2018/09/msg00010.html
- https://www.broadcom.com/support/fibre-channel-networking/security-advisories/brocade-security-advisory-2019-764
- https://cert-portal.siemens.com/productcert/pdf/ssa-412672.pdf