Vulnerabilities > CVE-2017-1081 - Improper Input Validation vulnerability in Freebsd

047910
CVSS 7.8 - HIGH
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
NONE
Integrity impact
NONE
Availability impact
COMPLETE
network
low complexity
freebsd
CWE-20
nessus

Summary

In FreeBSD before 11.0-STABLE, 11.0-RELEASE-p10, 10.3-STABLE, and 10.3-RELEASE-p19, ipfilter using "keep state" or "keep frags" options can cause a kernel panic when fed specially crafted packet fragments due to incorrect memory handling.

Vulnerable Configurations

Part Description Count
OS
Freebsd
800

Common Weakness Enumeration (CWE)

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Buffer Overflow via Environment Variables
    This attack pattern involves causing a buffer overflow through manipulation of environment variables. Once the attacker finds that they can modify an environment variable, they may try to overflow associated buffers. This attack leverages implicit trust often placed in environment variables.
  • Server Side Include (SSI) Injection
    An attacker can use Server Side Include (SSI) Injection to send code to a web application that then gets executed by the web server. Doing so enables the attacker to achieve similar results to Cross Site Scripting, viz., arbitrary code execution and information disclosure, albeit on a more limited scale, since the SSI directives are nowhere near as powerful as a full-fledged scripting language. Nonetheless, the attacker can conveniently gain access to sensitive files, such as password files, and execute shell commands.
  • Cross Zone Scripting
    An attacker is able to cause a victim to load content into their web-browser that bypasses security zone controls and gain access to increased privileges to execute scripting code or other web objects such as unsigned ActiveX controls or applets. This is a privilege elevation attack targeted at zone-based web-browser security. In a zone-based model, pages belong to one of a set of zones corresponding to the level of privilege assigned to that page. Pages in an untrusted zone would have a lesser level of access to the system and/or be restricted in the types of executable content it was allowed to invoke. In a cross-zone scripting attack, a page that should be assigned to a less privileged zone is granted the privileges of a more trusted zone. This can be accomplished by exploiting bugs in the browser, exploiting incorrect configuration in the zone controls, through a cross-site scripting attack that causes the attackers' content to be treated as coming from a more trusted page, or by leveraging some piece of system functionality that is accessible from both the trusted and less trusted zone. This attack differs from "Restful Privilege Escalation" in that the latter correlates to the inadequate securing of RESTful access methods (such as HTTP DELETE) on the server, while cross-zone scripting attacks the concept of security zones as implemented by a browser.
  • Cross Site Scripting through Log Files
    An attacker may leverage a system weakness where logs are susceptible to log injection to insert scripts into the system's logs. If these logs are later viewed by an administrator through a thin administrative interface and the log data is not properly HTML encoded before being written to the page, the attackers' scripts stored in the log will be executed in the administrative interface with potentially serious consequences. This attack pattern is really a combination of two other attack patterns: log injection and stored cross site scripting.
  • Command Line Execution through SQL Injection
    An attacker uses standard SQL injection methods to inject data into the command line for execution. This could be done directly through misuse of directives such as MSSQL_xp_cmdshell or indirectly through injection of data into the database that would be interpreted as shell commands. Sometime later, an unscrupulous backend application (or could be part of the functionality of the same application) fetches the injected data stored in the database and uses this data as command line arguments without performing proper validation. The malicious data escapes that data plane by spawning new commands to be executed on the host.

Nessus

  • NASL familyFreeBSD Local Security Checks
    NASL idFREEBSD_SA-17-04_IPFILTER.NASL
    descriptionThe version of the FreeBSD kernel running on the remote host is prior to 10.3-RELEASE-p19 or 11.0 prior to 11.0-RELEASE-p10. It, therefore, affected by a use-after-free error in the ipfilter kernel module (ipl.ko) due to freeing the wrong entry in a hash table when matching packet fragments are processed. An unauthenticated, remote attacker can exploit this issue, via specially crafted packet fragments, to cause a panic and reboot, resulting in a denial of service condition. Note that this issue only affects hosts with ipfilter enabled and the
    last seen2020-06-01
    modified2020-06-02
    plugin id99994
    published2017-05-05
    reporterThis script is Copyright (C) 2017-2018 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/99994
    titleFreeBSD < 10.3-RELEASE-p19 / 11.0 < 11.0-RELEASE-p10 ipfilter Kernel Module Packet Fragment DoS (FreeBSD-SA-17:04.ipfilter)
    code
    #
    # (C) Tenable Network Security, Inc.
    #
    
    include("compat.inc");
    
    if (description)
    {
      script_id(99994);
      script_version("1.8");
      script_cvs_date("Date: 2018/12/07 17:08:17");
    
      script_cve_id("CVE-2017-1081");
      script_bugtraq_id(98089);
    
      script_name(english:"FreeBSD < 10.3-RELEASE-p19 / 11.0 < 11.0-RELEASE-p10 ipfilter Kernel Module Packet Fragment DoS (FreeBSD-SA-17:04.ipfilter)");
      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-p19 or 11.0 prior to 11.0-RELEASE-p10. It, therefore,
    affected by a use-after-free error in the ipfilter kernel module
    (ipl.ko) due to freeing the wrong entry in a hash table when matching
    packet fragments are processed. An unauthenticated, remote attacker
    can exploit this issue, via specially crafted packet fragments, to
    cause a panic and reboot, resulting in a denial of service condition.
    
    Note that this issue only affects hosts with ipfilter enabled and the
    'keep state' or 'keep frags' rule options enabled.");
      # https://www.freebsd.org/security/advisories/FreeBSD-SA-17:04.ipfilter.asc
      script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?e471fb57");
      script_set_attribute(attribute:"solution", value:
    "Upgrade to FreeBSD version 10.3-RELEASE-p19 / 11.0-RELEASE-p10 or
    later. Alternatively, apply the patch referenced in the advisory.");
      script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C");
      script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
      script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H");
      script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
      script_set_attribute(attribute:"cvss_score_source", value:"CVE-2017-1081");
      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:"2017/04/27");
      script_set_attribute(attribute:"patch_publication_date", value:"2017/04/27");
      script_set_attribute(attribute:"plugin_publication_date", value:"2017/05/05");
    
      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 and is owned by Tenable, Inc. or an Affiliate thereof.");
    
      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");
    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");
    if (!get_kb_item("Host/FreeBSD/pkg_info")) audit(AUDIT_PACKAGE_LIST_MISSING);
    
    # Patches are available and ipfilter must be enabled with
    # "keep state" or "keep frags" rule options enabled
    if (report_paranoia < 2) audit(AUDIT_PARANOID);
    
    fix = NULL;
    
    if (release =~ "^FreeBSD-([0-9]|10\.[0-3])($|[^0-9])")
      fix = "FreeBSD-10.3_19";
    else if (release =~ "^FreeBSD-11\.0($|[^0-9])")
      fix = "FreeBSD-11.0_10";
    
    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_HOLE, extra:report);
    
  • NASL familyFreeBSD Local Security Checks
    NASL idFREEBSD_PKG_51D1282D420E11E782C514DAE9D210B8.NASL
    descriptionipfilter(4), capable of stateful packet inspection, using the
    last seen2020-06-01
    modified2020-06-02
    plugin id100497
    published2017-05-30
    reporterThis script is Copyright (C) 2017-2018 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/100497
    titleFreeBSD : FreeBSD -- ipfilter(4) fragment handling panic (51d1282d-420e-11e7-82c5-14dae9d210b8)