Vulnerabilities > CVE-2017-1087 - Path Traversal vulnerability in Freebsd

047910
CVSS 4.6 - MEDIUM
Attack vector
LOCAL
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
PARTIAL
Integrity impact
PARTIAL
Availability impact
PARTIAL
local
low complexity
freebsd
CWE-22
nessus

Summary

In FreeBSD 10.x before 10.4-STABLE, 10.4-RELEASE-p3, and 10.3-RELEASE-p24 named paths are globally scoped, meaning a process located in one jail can read and modify the content of POSIX shared memory objects created by a process in another jail or the host system. As a result, a malicious user that has access to a jailed system is able to abuse shared memory by injecting malicious content in the shared memory region. This memory region might be executed by applications trusting the shared memory, like Squid. This issue could lead to a Denial of Service or local privilege escalation.

Vulnerable Configurations

Part Description Count
OS
Freebsd
1

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Relative Path Traversal
    An attacker exploits a weakness in input validation on the target by supplying a specially constructed path utilizing dot and slash characters for the purpose of obtaining access to arbitrary files or resources. An attacker modifies a known path on the target in order to reach material that is not available through intended channels. These attacks normally involve adding additional path separators (/ or \) and/or dots (.), or encodings thereof, in various combinations in order to reach parent directories or entirely separate trees of the target's directory structure.
  • Directory Traversal
    An attacker with access to file system resources, either directly or via application logic, will use various file path specification or navigation mechanisms such as ".." in path strings and absolute paths to extend their range of access to inappropriate areas of the file system. The attacker attempts to either explore the file system for recon purposes or access directories and files that are intended to be restricted from their access. Exploring the file system can be achieved through constructing paths presented to directory listing programs, such as "ls" and 'dir', or through specially crafted programs that attempt to explore the file system. The attacker engaging in this type of activity is searching for information that can be used later in a more exploitive attack. Access to restricted directories or files can be achieved through modification of path references utilized by system applications.
  • File System Function Injection, Content Based
    An attack of this type exploits the host's trust in executing remote content including binary files. The files are poisoned with a malicious payload (targeting the file systems accessible by the target software) by the attacker and may be passed through standard channels such as via email, and standard web content like PDF and multimedia files. The attacker exploits known vulnerabilities or handling routines in the target processes. Vulnerabilities of this type have been found in a wide variety of commercial applications from Microsoft Office to Adobe Acrobat and Apple Safari web browser. When the attacker knows the standard handling routines and can identify vulnerabilities and entry points they can be exploited by otherwise seemingly normal content. Once the attack is executed, the attackers' program can access relative directories such as C:\Program Files or other standard system directories to launch further attacks. In a worst case scenario, these programs are combined with other propagation logic and work as a virus.
  • Using Slashes and URL Encoding Combined to Bypass Validation Logic
    This attack targets the encoding of the URL combined with the encoding of the slash characters. An attacker can take advantage of the multiple way of encoding an URL and abuse the interpretation of the URL. An URL may contain special character that need special syntax handling in order to be interpreted. Special characters are represented using a percentage character followed by two digits representing the octet code of the original character (%HEX-CODE). For instance US-ASCII space character would be represented with %20. This is often referred as escaped ending or percent-encoding. Since the server decodes the URL from the requests, it may restrict the access to some URL paths by validating and filtering out the URL requests it received. An attacker will try to craft an URL with a sequence of special characters which once interpreted by the server will be equivalent to a forbidden URL. It can be difficult to protect against this attack since the URL can contain other format of encoding such as UTF-8 encoding, Unicode-encoding, etc.
  • Manipulating Input to File System Calls
    An attacker manipulates inputs to the target software which the target software passes to file system calls in the OS. The goal is to gain access to, and perhaps modify, areas of the file system that the target software did not intend to be accessible.

Nessus

  • NASL familyFreeBSD Local Security Checks
    NASL idFREEBSD_SA-17-09_SHM.NASL
    descriptionThe version of the FreeBSD kernel running on the remote host is prior to 10.3-RELEASE-p24, or 10.4 prior to 10.4-RELEASE-p3. It is, therefore, affected by a potential information disclosure vulnerabilities in shm. An authenticated, remote attacker can exploit this issue by accessing the shared memory space in a jail to access and modify shared memory spaces in other jails. This can be used to target processes such as squid, and cause denials of service, or privilege escalations. Only systems running jails with local users are affected.
    last seen2020-06-01
    modified2020-06-02
    plugin id104971
    published2017-12-01
    reporterThis script is Copyright (C) 2017-2018 Tenable Network Security, Inc.
    sourcehttps://www.tenable.com/plugins/nessus/104971
    titleFreeBSD 10.3 / 10.4 : shm Insecure Memory Vulnerability (FreeBSD-SA-17:09.shm)
    code
    #
    # (C) Tenable Network Security, Inc.
    #
    
    include("compat.inc");
    
    if (description)
    {
      script_id(104971);
      script_version("1.8");
      script_cvs_date("Date: 2018/09/17 21:46:53");
    
      script_cve_id("CVE-2017-1087");
      script_bugtraq_id(101867);
    
      script_name(english:"FreeBSD 10.3 / 10.4 : shm Insecure Memory Vulnerability (FreeBSD-SA-17:09.shm)");
      script_summary(english:"Checks for the version of the FreeBSD kernel.");
    
      script_set_attribute(attribute:"synopsis", value:
    "The remote FreeBSD host is missing a security-related update.");
      script_set_attribute(attribute:"description", value:
    "The version of the FreeBSD kernel running on the remote host is prior
    to 10.3-RELEASE-p24, or 10.4 prior to 10.4-RELEASE-p3. It is,
    therefore, affected by a potential information disclosure
    vulnerabilities in shm. An authenticated, remote attacker can exploit
    this issue by accessing the shared memory space in a jail to access
    and modify shared memory spaces in other jails. This can be used to
    target processes such as squid, and cause denials of service, or
    privilege escalations.
    
    Only systems running jails with local users are affected.");
      # https://www.freebsd.org/security/advisories/FreeBSD-SA-17:09.shm.asc
      script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?0e9dd83e");
      script_set_attribute(attribute:"solution", value:
    "Upgrade to the appropriate FreeBSD version.");
      script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:N/C:P/I:P/A:P");
      script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
      script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L");
      script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
      script_set_attribute(attribute:"cvss_score_source", value:"CVE-2017-1087");
      script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
      script_set_attribute(attribute:"exploit_available", value:"false");
    
      script_set_attribute(attribute:"vuln_publication_date", value:"2017/11/15");
      script_set_attribute(attribute:"patch_publication_date", value:"2017/11/15");
      script_set_attribute(attribute:"plugin_publication_date", value:"2017/12/01");
    
      script_set_attribute(attribute:"plugin_type", value:"local");
      script_set_attribute(attribute:"cpe", value:"cpe:/o:freebsd:freebsd");
      script_set_attribute(attribute:"potential_vulnerability", value:"true");
      script_end_attributes();
    
      script_category(ACT_GATHER_INFO);
      script_family(english:"FreeBSD Local Security Checks");
    
      script_copyright(english:"This script is Copyright (C) 2017-2018 Tenable Network Security, Inc.");
    
      script_dependencies("ssh_get_info.nasl");
      script_require_keys("Host/local_checks_enabled", "Host/FreeBSD/release", "Settings/ParanoidReport");
    
      exit(0);
    }
    
    include("audit.inc");
    include("freebsd_package.inc");
    include("misc_func.inc");
    
    if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
    release = get_kb_item("Host/FreeBSD/release");
    if (!release) audit(AUDIT_OS_NOT, "FreeBSD");
    
    # Patches are available, require paranoid since it is possible
    # to manually patch and have a lower OS level.
    if (report_paranoia < 2) audit(AUDIT_PARANOID);
    
    fix = NULL;
    
    if (release =~ "^FreeBSD-([0-9]|10\.[0-3])($|[^0-9])")
      fix = "FreeBSD-10.3_24";
    else if (release =~ "^FreeBSD-10\.4($|[^0-9])")
      fix = "FreeBSD-10.4_3";
    
    if (isnull(fix) || pkg_cmp(pkg:release, reference:fix) >= 0)
      audit(AUDIT_HOST_NOT, "affected");
    
    report =
      '\n  Installed version : ' + release +
      '\n  Fixed version     : ' + fix +
      '\n';
    security_report_v4(port:0, severity:SECURITY_WARNING, extra:report);
    
  • NASL familyFreeBSD Local Security Checks
    NASL idFREEBSD_PKG_5B1463DDDAB311E7B5AFA4BADB2F4699.NASL
    descriptionNamed paths are globally scoped, meaning a process located in one jail can read and modify the content of POSIX shared memory objects created by a process in another jail or the host system. Impact : A malicious user that has access to a jailed system is able to abuse shared memory by injecting malicious content in the shared memory region. This memory region might be executed by applications trusting the shared memory, like Squid. This issue could lead to a Denial of Service or local privilege escalation.
    last seen2020-06-01
    modified2020-06-02
    plugin id105065
    published2017-12-07
    reporterThis script is Copyright (C) 2017-2018 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/105065
    titleFreeBSD : FreeBSD -- POSIX shm allows jails to access global namespace (5b1463dd-dab3-11e7-b5af-a4badb2f4699)
    code
    #
    # (C) Tenable Network Security, Inc.
    #
    # The descriptive text and package checks in this plugin were  
    # extracted from the FreeBSD VuXML database :
    #
    # Copyright 2003-2018 Jacques Vidrine and contributors
    #
    # Redistribution and use in source (VuXML) and 'compiled' forms (SGML,
    # HTML, PDF, PostScript, RTF and so forth) with or without modification,
    # are permitted provided that the following conditions are met:
    # 1. Redistributions of source code (VuXML) must retain the above
    #    copyright notice, this list of conditions and the following
    #    disclaimer as the first lines of this file unmodified.
    # 2. Redistributions in compiled form (transformed to other DTDs,
    #    published online in any format, converted to PDF, PostScript,
    #    RTF and other formats) must reproduce the above copyright
    #    notice, this list of conditions and the following disclaimer
    #    in the documentation and/or other materials provided with the
    #    distribution.
    # 
    # THIS DOCUMENTATION IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS"
    # AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
    # THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
    # PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
    # BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
    # OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
    # OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
    # BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
    # WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
    # OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS DOCUMENTATION,
    # EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
    #
    
    include("compat.inc");
    
    if (description)
    {
      script_id(105065);
      script_version("3.4");
      script_cvs_date("Date: 2018/12/07  9:46:53");
    
      script_cve_id("CVE-2017-1087");
      script_xref(name:"FreeBSD", value:"SA-17:09.shm");
    
      script_name(english:"FreeBSD : FreeBSD -- POSIX shm allows jails to access global namespace (5b1463dd-dab3-11e7-b5af-a4badb2f4699)");
      script_summary(english:"Checks for updated packages in pkg_info output");
    
      script_set_attribute(
        attribute:"synopsis", 
        value:
    "The remote FreeBSD host is missing one or more security-related
    updates."
      );
      script_set_attribute(
        attribute:"description", 
        value:
    "Named paths are globally scoped, meaning a process located in one jail
    can read and modify the content of POSIX shared memory objects created
    by a process in another jail or the host system. Impact : A malicious
    user that has access to a jailed system is able to abuse shared memory
    by injecting malicious content in the shared memory region. This
    memory region might be executed by applications trusting the shared
    memory, like Squid.
    
    This issue could lead to a Denial of Service or local privilege
    escalation."
      );
      # https://vuxml.freebsd.org/freebsd/5b1463dd-dab3-11e7-b5af-a4badb2f4699.html
      script_set_attribute(
        attribute:"see_also",
        value:"http://www.nessus.org/u?15166dcf"
      );
      script_set_attribute(attribute:"solution", value:"Update the affected packages.");
      script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:N/C:P/I:P/A:P");
      script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H");
    
      script_set_attribute(attribute:"plugin_type", value:"local");
      script_set_attribute(attribute:"cpe", value:"p-cpe:/a:freebsd:freebsd:FreeBSD");
      script_set_attribute(attribute:"cpe", value:"cpe:/o:freebsd:freebsd");
    
      script_set_attribute(attribute:"vuln_publication_date", value:"2017/11/15");
      script_set_attribute(attribute:"patch_publication_date", value:"2017/12/06");
      script_set_attribute(attribute:"plugin_publication_date", value:"2017/12/07");
      script_end_attributes();
    
      script_category(ACT_GATHER_INFO);
      script_copyright(english:"This script is Copyright (C) 2017-2018 and is owned by Tenable, Inc. or an Affiliate thereof.");
      script_family(english:"FreeBSD Local Security Checks");
    
      script_dependencies("ssh_get_info.nasl");
      script_require_keys("Host/local_checks_enabled", "Host/FreeBSD/release", "Host/FreeBSD/pkg_info", "Settings/ParanoidReport");
    
      exit(0);
    }
    
    
    include("audit.inc");
    include("freebsd_package.inc");
    
    
    if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
    if (!get_kb_item("Host/FreeBSD/release")) audit(AUDIT_OS_NOT, "FreeBSD");
    if (!get_kb_item("Host/FreeBSD/pkg_info")) audit(AUDIT_PACKAGE_LIST_MISSING);
    
    
    if (report_paranoia < 2) audit(AUDIT_PARANOID);
    
    flag = 0;
    
    if (pkg_test(save_report:TRUE, pkg:"FreeBSD>=10.4<10.4_3")) flag++;
    if (pkg_test(save_report:TRUE, pkg:"FreeBSD>=10.3<10.3_24")) flag++;
    
    if (flag)
    {
      if (report_verbosity > 0) security_warning(port:0, extra:pkg_report_get());
      else security_warning(0);
      exit(0);
    }
    else audit(AUDIT_HOST_NOT, "affected");