Vulnerabilities > CVE-2011-0017 - Improper Input Validation vulnerability in Exim

047910
CVSS 6.9 - MEDIUM
Attack vector
LOCAL
Attack complexity
MEDIUM
Privileges required
NONE
Confidentiality impact
COMPLETE
Integrity impact
COMPLETE
Availability impact
COMPLETE
local
exim
CWE-20
nessus

Summary

The open_log function in log.c in Exim 4.72 and earlier does not check the return value from (1) setuid or (2) setgid system calls, which allows local users to append log data to arbitrary files via a symlink attack.

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 familySuSE Local Security Checks
    NASL idSUSE_11_2_EXIM-110207.NASL
    descriptionExim was updated to verify the return value of the setuid/setgid calls now. (CVE-2011-0017: CVSS v2 Base Score: 6.9 (AV:L/AC:M/Au:N/C:C/I:C/A:C): Link Following (CWE-59))
    last seen2020-06-01
    modified2020-06-02
    plugin id53716
    published2011-05-05
    reporterThis script is Copyright (C) 2011-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/53716
    titleopenSUSE Security Update : exim (openSUSE-SU-2011:0105-1)
    code
    #%NASL_MIN_LEVEL 80502
    #
    # (C) Tenable Network Security, Inc.
    #
    # The descriptive text and package checks in this plugin were
    # extracted from openSUSE Security Update exim-3922.
    #
    # The text description of this plugin is (C) SUSE LLC.
    #
    
    include("compat.inc");
    
    if (description)
    {
      script_id(53716);
      script_version("1.5");
      script_cvs_date("Date: 2019/10/25 13:36:40");
    
      script_cve_id("CVE-2011-0017");
    
      script_name(english:"openSUSE Security Update : exim (openSUSE-SU-2011:0105-1)");
      script_summary(english:"Check for the exim-3922 patch");
    
      script_set_attribute(
        attribute:"synopsis", 
        value:"The remote openSUSE host is missing a security update."
      );
      script_set_attribute(
        attribute:"description", 
        value:
    "Exim was updated to verify the return value of the setuid/setgid calls
    now. (CVE-2011-0017: CVSS v2 Base Score: 6.9
    (AV:L/AC:M/Au:N/C:C/I:C/A:C): Link Following (CWE-59))"
      );
      script_set_attribute(
        attribute:"see_also",
        value:"https://bugzilla.novell.com/show_bug.cgi?id=668599"
      );
      script_set_attribute(
        attribute:"see_also",
        value:"https://lists.opensuse.org/opensuse-updates/2011-02/msg00005.html"
      );
      script_set_attribute(attribute:"solution", value:"Update the affected exim packages.");
      script_set_cvss_base_vector("CVSS2#AV:L/AC:M/Au:N/C:C/I:C/A:C");
    
      script_set_attribute(attribute:"plugin_type", value:"local");
      script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:opensuse:exim");
      script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:opensuse:eximon");
      script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:opensuse:eximstats-html");
      script_set_attribute(attribute:"cpe", value:"cpe:/o:novell:opensuse:11.2");
    
      script_set_attribute(attribute:"patch_publication_date", value:"2011/02/07");
      script_set_attribute(attribute:"plugin_publication_date", value:"2011/05/05");
      script_end_attributes();
    
      script_category(ACT_GATHER_INFO);
      script_copyright(english:"This script is Copyright (C) 2011-2019 and is owned by Tenable, Inc. or an Affiliate thereof.");
      script_family(english:"SuSE Local Security Checks");
    
      script_dependencies("ssh_get_info.nasl");
      script_require_keys("Host/local_checks_enabled", "Host/SuSE/release", "Host/SuSE/rpm-list", "Host/cpu");
    
      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/SuSE/release");
    if (isnull(release) || release =~ "^(SLED|SLES)") audit(AUDIT_OS_NOT, "openSUSE");
    if (release !~ "^(SUSE11\.2)$") audit(AUDIT_OS_RELEASE_NOT, "openSUSE", "11.2", release);
    if (!get_kb_item("Host/SuSE/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);
    
    ourarch = get_kb_item("Host/cpu");
    if (!ourarch) audit(AUDIT_UNKNOWN_ARCH);
    if (ourarch !~ "^(i586|i686|x86_64)$") audit(AUDIT_ARCH_NOT, "i586 / i686 / x86_64", ourarch);
    
    flag = 0;
    
    if ( rpm_check(release:"SUSE11.2", reference:"exim-4.69-72.8.1") ) flag++;
    if ( rpm_check(release:"SUSE11.2", reference:"eximon-4.69-72.8.1") ) flag++;
    if ( rpm_check(release:"SUSE11.2", reference:"eximstats-html-4.69-72.8.1") ) 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, "exim");
    }
    
  • NASL familyDebian Local Security Checks
    NASL idDEBIAN_DSA-2154.NASL
    descriptionA design flaw (CVE-2010-4345 ) in exim4 allowed the local Debian-exim user to obtain root privileges by specifying an alternate configuration file using the -C option or by using the macro override facility (-D option). Unfortunately, fixing this vulnerability is not possible without some changes in exim4
    last seen2020-03-17
    modified2011-01-31
    plugin id51819
    published2011-01-31
    reporterThis script is Copyright (C) 2011-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/51819
    titleDebian DSA-2154-1 : exim4 - privilege escalation
  • NASL familySuSE Local Security Checks
    NASL idSUSE_11_3_EXIM-110207.NASL
    descriptionExim was updated to verify the return value of the setuid/setgid calls now. (CVE-2011-0017: CVSS v2 Base Score: 6.9 (AV:L/AC:M/Au:N/C:C/I:C/A:C): Link Following (CWE-59))
    last seen2020-06-01
    modified2020-06-02
    plugin id75482
    published2014-06-13
    reporterThis script is Copyright (C) 2014-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/75482
    titleopenSUSE Security Update : exim (openSUSE-SU-2011:0105-1)
  • NASL familyUbuntu Local Security Checks
    NASL idUBUNTU_USN-1060-1.NASL
    descriptionIt was discovered that Exim contained a design flaw in the way it processed alternate configuration files. An attacker that obtained privileges of the
    last seen2020-06-01
    modified2020-06-02
    plugin id51954
    published2011-02-11
    reporterUbuntu Security Notice (C) 2011-2019 Canonical, Inc. / NASL script (C) 2011-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/51954
    titleUbuntu 6.06 LTS / 8.04 LTS / 9.10 / 10.04 LTS / 10.10 : exim4 vulnerabilities (USN-1060-1)
  • NASL familyFreeBSD Local Security Checks
    NASL idFREEBSD_PKG_44CCFAB0356411E08E810022190034C0.NASL
    descriptionexim.org reports : CVE-2011-0017 - check return value of setuid/setgid. This is a privilege escalation vulnerability whereby the Exim run-time user can cause root to append content of the attacker
    last seen2020-06-01
    modified2020-06-02
    plugin id51963
    published2011-02-14
    reporterThis script is Copyright (C) 2011-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/51963
    titleFreeBSD : exim -- local privilege escalation (44ccfab0-3564-11e0-8e81-0022190034c0)
  • NASL familySMTP problems
    NASL idEXIM_4_74.NASL
    descriptionThe remote host is running Exim, a message transfer agent. According to the version number in its banner, the installed version of Exim is earlier than 4.74 and thus potentially affected by a local privilege escalation vulnerability. If the remote host is running Linux, attackers can exploit this issue to append arbitrary data to files through symbolic link attacks. Successfully exploiting this issue allows local attackers with
    last seen2020-06-01
    modified2020-06-02
    plugin id51861
    published2011-02-03
    reporterThis script is Copyright (C) 2011-2018 Tenable Network Security, Inc.
    sourcehttps://www.tenable.com/plugins/nessus/51861
    titleExim < 4.74 Local Privilege Escalation
  • NASL familyGentoo Local Security Checks
    NASL idGENTOO_GLSA-201401-32.NASL
    descriptionThe remote host is affected by the vulnerability described in GLSA-201401-32 (Exim: Multiple vulnerabilities) Multiple vulnerabilities have been discovered in Exim. Please review the CVE identifiers referenced below for details. Impact : A remote attacker could possibly execute arbitrary code with root privileges, or cause a Denial of Service condition. Workaround : There is no known workaround at this time.
    last seen2020-06-01
    modified2020-06-02
    plugin id72159
    published2014-01-28
    reporterThis script is Copyright (C) 2014-2018 Tenable Network Security, Inc.
    sourcehttps://www.tenable.com/plugins/nessus/72159
    titleGLSA-201401-32 : Exim: Multiple vulnerabilities