Vulnerabilities > CVE-2012-0871 - Link Following vulnerability in multiple products

047910
CVSS 6.3 - MEDIUM
Attack vector
LOCAL
Attack complexity
MEDIUM
Privileges required
NONE
Confidentiality impact
NONE
Integrity impact
COMPLETE
Availability impact
COMPLETE
local
systemd-project
opensuse
CWE-59
nessus
NVD
Published: 2014-04-18
Updated: 2022-01-28

Summary

The session_link_x11_socket function in login/logind-session.c in systemd-logind in systemd, possibly 37 and earlier, allows local users to create or overwrite arbitrary files via a symlink attack on the X11 user directory in /run/user/.

Vulnerable Configurations

Part Description Count
Application
Systemd_Project
37
OS
Opensuse
1

Common Weakness Enumeration (CWE)

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Symlink Attack
    An attacker positions a symbolic link in such a manner that the targeted user or application accesses the link's endpoint, assuming that it is accessing a file with the link's name. The endpoint file may be either output or input. If the file is output, the result is that the endpoint is modified, instead of a file at the intended location. Modifications to the endpoint file may include appending, overwriting, corrupting, changing permissions, or other modifications. In some variants of this attack the attacker may be able to control the change to a file while in other cases they cannot. The former is especially damaging since the attacker may be able to grant themselves increased privileges or insert false information, but the latter can also be damaging as it can expose sensitive information or corrupt or destroy vital system or application files. Alternatively, the endpoint file may serve as input to the targeted application. This can be used to feed malformed input into the target or to cause the target to process different information, possibly allowing the attacker to control the actions of the target or to cause the target to expose information to the attacker. Moreover, the actions taken on the endpoint file are undertaken with the permissions of the targeted user or application, which may exceed the permissions that the attacker would normally have.
  • 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.
  • 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 familyFedora Local Security Checks
    NASL idFEDORA_2012-2557.NASL
    descriptionThis systemd update adds several fixes : - logind created files under /run/user/ in an insecure manner. A local attacker could create a symlink inside arbitrary directories (CVE-2012-0871). - permissions of PrivateTmp directories (RHBZ#790522) - timedated did not run without ntp installed (RHBZ#790260) - logind: allow PowerOff and Reboot via polkit - loading of empty files in read_one_line_file() (fdo#45362) - fix cgit URLs in manpages 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 seen2020-03-17
    modified2012-03-12
    plugin id58308
    published2012-03-12
    reporterThis script is Copyright (C) 2012-2020 Tenable Network Security, Inc.
    sourcehttps://www.tenable.com/plugins/nessus/58308
    titleFedora 16 : systemd-37-15.fc16 (2012-2557)
    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 2012-2557.
#

include("compat.inc");

if (description)
{
  script_id(58308);
  script_version("1.10");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/03/12");

  script_cve_id("CVE-2012-0871");
  script_bugtraq_id(52230);
  script_xref(name:"FEDORA", value:"2012-2557");

  script_name(english:"Fedora 16 : systemd-37-15.fc16 (2012-2557)");
  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:
"This systemd update adds several fixes :

  - logind created files under /run/user/ in an insecure
    manner. A local attacker could create a symlink inside
    arbitrary directories (CVE-2012-0871).

    - permissions of PrivateTmp directories (RHBZ#790522)

    - timedated did not run without ntp installed
      (RHBZ#790260)

    - logind: allow PowerOff and Reboot via polkit

    - loading of empty files in read_one_line_file()
      (fdo#45362)

    - fix cgit URLs in manpages

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=795853"
  );
  # https://lists.fedoraproject.org/pipermail/package-announce/2012-March/075107.html
  script_set_attribute(
    attribute:"see_also",
    value:"http://www.nessus.org/u?2703d158"
  );
  script_set_attribute(
    attribute:"solution", 
    value:"Update the affected systemd package."
  );
  script_set_cvss_base_vector("CVSS2#AV:L/AC:M/Au:N/C:N/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:F/RL:OF/RC:C");
  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fedoraproject:fedora:systemd");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:fedoraproject:fedora:16");

  script_set_attribute(attribute:"patch_publication_date", value:"2012/02/28");
  script_set_attribute(attribute:"plugin_publication_date", value:"2012/03/12");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2012-2020 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:"^16([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, "Fedora 16.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:"FC16", reference:"systemd-37-15.fc16")) 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, "systemd");
}
  • NASL familySuSE Local Security Checks
    NASL idOPENSUSE-2012-139.NASL
    description - Add fix-console-switch.patch: prevent console lockup (rhb#771563). - Add fix-quota.patch: correctly enable quota (rhb#773431). - Add passcredentials.patch: ensure compatibility with kernel 3.2 (bnc#743299). - Update modules_on_boot.patch to not cause failed state for systemd-modules-load.service (bnc#741481). - Ensure systemd show service status when started behind bootsplash and don
    last seen2020-06-05
    modified2014-06-13
    plugin id74560
    published2014-06-13
    reporterThis script is Copyright (C) 2014-2020 Tenable Network Security, Inc.
    sourcehttps://www.tenable.com/plugins/nessus/74560
    titleopenSUSE Security Update : systemd (openSUSE-2012-139)
    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 openSUSE-2012-139.
#
# The text description of this plugin is (C) SUSE LLC.
#

include("compat.inc");

if (description)
{
  script_id(74560);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/06/04");

  script_cve_id("CVE-2012-0871");

  script_name(english:"openSUSE Security Update : systemd (openSUSE-2012-139)");
  script_summary(english:"Check for the openSUSE-2012-139 patch");

  script_set_attribute(
    attribute:"synopsis", 
    value:"The remote openSUSE host is missing a security update."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"  - Add fix-console-switch.patch: prevent console lockup
    (rhb#771563).

  - Add fix-quota.patch: correctly enable quota
    (rhb#773431).

  - Add passcredentials.patch: ensure compatibility with
    kernel 3.2 (bnc#743299).

  - Update modules_on_boot.patch to not cause failed state
    for systemd-modules-load.service (bnc#741481).

  - Ensure systemd show service status when started behind
    bootsplash and don't try to start when bootsplash isn't
    installed (bnc#736225).

  - Add fix-proc-net-unix-parsing.patch: fix /tmp socket
    cleanup on 32bits (mmeeks) (bnc#739438).

  - Add improve-readahead.patch: don't monopolize IO when
    replaying (git).

  - Add sysv_to_syslog_and_console.patch: ensure sysv
    services output is logged to syslog in addition to
    console (improve bnc#731342, bnc#681127).

  - Add fix-daemon-reload-reaping.patch: fix activating
    service being killed if daemon-reload is started (git).

  - Add no-variable-tcpwrappers.patch: fix manpage for
    tcpwrapper support (bnc#741023).

  - Add remote-fs-after-network.patch and update insserv
    patch: ensure remote-fs-pre.target is enabled and
    started before network mount points (bnc#744293).

  - Add dm-lvm-after-local-fs-pre-target.patch: ensure md /
    lvm /dmraid is started before mounting partitions, if
    fsck was disabled for them (bnc#733283).

  - Update lsb-header patch to correctly disable heuristic
    if X-Systemd-RemainAfterExit is specified (whatever its
    value)

  - Add fix-message-after-chkconfig.patch: don't complain if
    only sysv services are called in systemctl.

  - Add is-enabled-non-existing-service.patch: fix error
    message when running is-enabled on non-existing service.

  - Add remove-timedated-ntp-dependency.patch: don't require
    ntp to use timedated (partially fixes bnc#734831).

  - Add move-x11-socket.patch: change X11 socket symlink
    name (bnc#747154).

  - Add fix-is-enabled.patch: ensure systemctl is-enabled
    work properly when systemd isn't running.

  - Add logind-console.patch: do not bail logind if
    /dev/tty0 doesn't exist (bnc#733022, bnc#735047).

  - Add sysctl-modules.patch: ensure sysctl is started after
    modules are loaded (bnc#725412).

  - Fix warning in insserv patch.

  - Update avoid-random-seed-cycle.patch with better
    upstream approach.

  - Update storage-after-cryptsetup.patch to restart lvm
    before local-fs.target, not after it (bnc#740106).

  - Increase pam-config dependency (bnc#713319)."
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bugzilla.novell.com/show_bug.cgi?id=681127"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bugzilla.novell.com/show_bug.cgi?id=713319"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bugzilla.novell.com/show_bug.cgi?id=725412"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bugzilla.novell.com/show_bug.cgi?id=731342"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bugzilla.novell.com/show_bug.cgi?id=733022"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bugzilla.novell.com/show_bug.cgi?id=733283"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bugzilla.novell.com/show_bug.cgi?id=734831"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bugzilla.novell.com/show_bug.cgi?id=735047"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bugzilla.novell.com/show_bug.cgi?id=736225"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bugzilla.novell.com/show_bug.cgi?id=739438"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bugzilla.novell.com/show_bug.cgi?id=740106"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bugzilla.novell.com/show_bug.cgi?id=741023"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bugzilla.novell.com/show_bug.cgi?id=741481"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bugzilla.novell.com/show_bug.cgi?id=743299"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bugzilla.novell.com/show_bug.cgi?id=744293"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bugzilla.novell.com/show_bug.cgi?id=747154"
  );
  script_set_attribute(
    attribute:"solution", 
    value:"Update the affected systemd packages."
  );
  script_set_cvss_base_vector("CVSS2#AV:L/AC:M/Au:N/C:N/I:C/A:C");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:opensuse:systemd");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:opensuse:systemd-32bit");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:opensuse:systemd-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:opensuse:systemd-debuginfo-32bit");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:opensuse:systemd-debugsource");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:opensuse:systemd-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:opensuse:systemd-sysvinit");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:novell:opensuse:12.1");

  script_set_attribute(attribute:"patch_publication_date", value:"2012/02/29");
  script_set_attribute(attribute:"plugin_publication_date", value:"2014/06/13");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2014-2020 Tenable Network Security, Inc.");
  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 !~ "^(SUSE12\.1)$") audit(AUDIT_OS_RELEASE_NOT, "openSUSE", "12.1", 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:"SUSE12.1", reference:"systemd-37-3.8.1") ) flag++;
if ( rpm_check(release:"SUSE12.1", reference:"systemd-debuginfo-37-3.8.1") ) flag++;
if ( rpm_check(release:"SUSE12.1", reference:"systemd-debugsource-37-3.8.1") ) flag++;
if ( rpm_check(release:"SUSE12.1", reference:"systemd-devel-37-3.8.1") ) flag++;
if ( rpm_check(release:"SUSE12.1", reference:"systemd-sysvinit-37-3.8.1") ) flag++;
if ( rpm_check(release:"SUSE12.1", cpu:"x86_64", reference:"systemd-32bit-37-3.8.1") ) flag++;
if ( rpm_check(release:"SUSE12.1", cpu:"x86_64", reference:"systemd-debuginfo-32bit-37-3.8.1") ) 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, "systemd-32bit / systemd / systemd-debuginfo-32bit / etc");
}

References