Vulnerabilities > CVE-2011-0491 - Improper Input Validation vulnerability in TOR

047910
CVSS 5.0 - MEDIUM
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
NONE
Integrity impact
NONE
Availability impact
PARTIAL
network
low complexity
tor
CWE-20
nessus

Summary

The tor_realloc function in Tor before 0.2.1.29 and 0.2.2.x before 0.2.2.21-alpha does not validate a certain size value during memory allocation, which might allow remote attackers to cause a denial of service (daemon crash) via unspecified vectors, related to "underflow errors."

Vulnerable Configurations

Part Description Count
Application
Tor
207

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 familyFedora Local Security Checks
    NASL idFEDORA_2011-0650.NASL
    description - Mon Jan 17 2011 Enrico Scholz <enrico.scholz at informatik.tu-chemnitz.de> - 0.2.1.29-1300 - updated to 0.2.1.29 (SECURITY) - CVE-2011-0427: heap overflow bug, potential remote code execution - Tue Dec 21 2010 Luke Macken <lmacken at redhat.com> - 0.2.1.28-1300 - updated to 0.2.1.28 (SECURITY: fixes a remotely exploitable heap overflow bug) - Fri Nov 26 2010 Enrico Scholz <enrico.scholz at informatik.tu-chemnitz.de> - 0.2.1.27-1300 - updated to 0.2.1.27 - work around broken chkconfig by adding dummy Default-Start: in -lsb (#647512) - Fri Nov 26 2010 Enrico Scholz <enrico.scholz at informatik.tu-chemnitz.de> - fixed
    last seen2020-06-01
    modified2020-06-02
    plugin id55002
    published2011-06-09
    reporterThis script is Copyright (C) 2011-2019 Tenable Network Security, Inc.
    sourcehttps://www.tenable.com/plugins/nessus/55002
    titleFedora 13 : tor-0.2.1.29-1300.fc13 (2011-0650)
    code
    #%NASL_MIN_LEVEL 80502
    #
    # (C) Tenable Network Security, Inc.
    #
    # The descriptive text and package checks in this plugin were  
    # extracted from Fedora Security Advisory 2011-0650.
    #
    
    include("compat.inc");
    
    if (description)
    {
      script_id(55002);
      script_version("1.10");
      script_cvs_date("Date: 2019/08/02 13:32:33");
    
      script_cve_id("CVE-2011-0015", "CVE-2011-0016", "CVE-2011-0427", "CVE-2011-0490", "CVE-2011-0491", "CVE-2011-0492", "CVE-2011-0493");
      script_bugtraq_id(45832, 45953);
      script_xref(name:"FEDORA", value:"2011-0650");
    
      script_name(english:"Fedora 13 : tor-0.2.1.29-1300.fc13 (2011-0650)");
      script_summary(english:"Checks rpm output for the updated package.");
    
      script_set_attribute(
        attribute:"synopsis", 
        value:"The remote Fedora host is missing a security update."
      );
      script_set_attribute(
        attribute:"description", 
        value:
    "  - Mon Jan 17 2011 Enrico Scholz <enrico.scholz at
        informatik.tu-chemnitz.de> - 0.2.1.29-1300
    
        - updated to 0.2.1.29 (SECURITY)
    
        - CVE-2011-0427: heap overflow bug, potential remote
          code execution
    
        - Tue Dec 21 2010 Luke Macken <lmacken at redhat.com> -
          0.2.1.28-1300
    
        - updated to 0.2.1.28 (SECURITY: fixes a remotely
          exploitable heap overflow bug)
    
        - Fri Nov 26 2010 Enrico Scholz <enrico.scholz at
          informatik.tu-chemnitz.de> - 0.2.1.27-1300
    
        - updated to 0.2.1.27
    
        - work around broken chkconfig by adding dummy
          Default-Start: in -lsb (#647512)
    
        - Fri Nov 26 2010 Enrico Scholz <enrico.scholz at
          informatik.tu-chemnitz.de>
    
        - fixed 'limit' statement in upstart script
    
        - Tue Jun 1 2010 Enrico Scholz <enrico.scholz at
          informatik.tu-chemnitz.de> - 0.2.1.26-1300
    
        - updated to 0.2.1.26
    
        - removed workaround to install lsb initscript because
          parts of the underlying problem have been fixed in
          redhat-lsb and the remaining ones were solved by
          previous commit
    
      - Tue Jun 1 2010 Enrico Scholz <enrico.scholz at
        informatik.tu-chemnitz.de> - 0.2.1.25-1301
    
        - removed $local_fs dependency in -lsb initscript to
          workaround buggy redhat-lsb; $remote_fs should imply
          it
    
      - Thu Mar 18 2010 Enrico Scholz <enrico.scholz at
        informatik.tu-chemnitz.de> - 0.2.1.25-1300
    
        - updated to 0.2.1.25
    
    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."
      );
      script_set_attribute(
        attribute:"see_also",
        value:"https://bugzilla.redhat.com/show_bug.cgi?id=671259"
      );
      # https://lists.fedoraproject.org/pipermail/package-announce/2011-June/061286.html
      script_set_attribute(
        attribute:"see_also",
        value:"http://www.nessus.org/u?204d659a"
      );
      script_set_attribute(attribute:"solution", value:"Update the affected tor package.");
      script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:P/I:P/A:P");
      script_set_cvss_temporal_vector("CVSS2#E:ND/RL:OF/RC:C");
      script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
      script_set_attribute(attribute:"exploit_available", value:"false");
    
      script_set_attribute(attribute:"plugin_type", value:"local");
      script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fedoraproject:fedora:tor");
      script_set_attribute(attribute:"cpe", value:"cpe:/o:fedoraproject:fedora:13");
    
      script_set_attribute(attribute:"patch_publication_date", value:"2011/01/21");
      script_set_attribute(attribute:"plugin_publication_date", value:"2011/06/09");
      script_end_attributes();
    
      script_category(ACT_GATHER_INFO);
      script_copyright(english:"This script is Copyright (C) 2011-2019 Tenable Network Security, Inc.");
      script_family(english:"Fedora Local Security Checks");
    
      script_dependencies("ssh_get_info.nasl");
      script_require_keys("Host/local_checks_enabled", "Host/RedHat/release", "Host/RedHat/rpm-list");
    
      exit(0);
    }
    
    
    include("audit.inc");
    include("global_settings.inc");
    include("rpm.inc");
    
    if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
    release = get_kb_item("Host/RedHat/release");
    if (isnull(release) || "Fedora" >!< release) audit(AUDIT_OS_NOT, "Fedora");
    os_ver = eregmatch(pattern: "Fedora.*release ([0-9]+)", string:release);
    if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "Fedora");
    os_ver = os_ver[1];
    if (! ereg(pattern:"^13([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, "Fedora 13.x", "Fedora " + os_ver);
    
    if (!get_kb_item("Host/RedHat/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);
    
    cpu = get_kb_item("Host/cpu");
    if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
    if ("x86_64" >!< cpu && cpu !~ "^i[3-6]86$") audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, "Fedora", cpu);
    
    flag = 0;
    if (rpm_check(release:"FC13", reference:"tor-0.2.1.29-1300.fc13")) flag++;
    
    
    if (flag)
    {
      if (report_verbosity > 0) security_warning(port:0, extra:rpm_report_get());
      else security_warning(0);
      exit(0);
    }
    else
    {
      tested = pkg_tests_get();
      if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
      else audit(AUDIT_PACKAGE_NOT_INSTALLED, "tor");
    }
    
  • NASL familyFedora Local Security Checks
    NASL idFEDORA_2011-0642.NASL
    description - Mon Jan 17 2011 Enrico Scholz <enrico.scholz at informatik.tu-chemnitz.de> - 0.2.1.29-1400 - updated to 0.2.1.29 (SECURITY) - CVE-2011-0427: heap overflow bug, potential remote code execution - Tue Dec 21 2010 Luke Macken <lmacken at redhat.com> - 0.2.1.28-1400 - updated to 0.2.1.28 (SECURITY: fixes a remotely exploitable heap overflow bug) - Fri Nov 26 2010 Enrico Scholz <enrico.scholz at informatik.tu-chemnitz.de> - 0.2.1.27-1400 - updated to 0.2.1.27 - work around broken chkconfig by adding dummy Default-Start: in -lsb (#647512) - Fri Nov 26 2010 Enrico Scholz <enrico.scholz at informatik.tu-chemnitz.de> - 0.2.1.26-1401 - fixed
    last seen2020-06-01
    modified2020-06-02
    plugin id53901
    published2011-05-16
    reporterThis script is Copyright (C) 2011-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/53901
    titleFedora 14 : tor-0.2.1.29-1400.fc14 (2011-0642)
  • NASL familyGentoo Local Security Checks
    NASL idGENTOO_GLSA-201110-13.NASL
    descriptionThe remote host is affected by the vulnerability described in GLSA-201110-13 (Tor: Multiple vulnerabilities) Multiple vulnerabilities have been discovered in Tor. Please review the CVE identifiers referenced below for details. Impact : A remote unauthenticated attacker may be able to execute arbitrary code with the privileges of the Tor process or create a Denial of Service. Workaround : There is no known workaround at this time.
    last seen2020-06-01
    modified2020-06-02
    plugin id56549
    published2011-10-19
    reporterThis script is Copyright (C) 2011-2018 Tenable Network Security, Inc.
    sourcehttps://www.tenable.com/plugins/nessus/56549
    titleGLSA-201110-13 : Tor: Multiple vulnerabilities