Vulnerabilities > CVE-2015-7496 - Permissions, Privileges, and Access Controls vulnerability in multiple products

047910
CVSS 7.2 - HIGH
Attack vector
LOCAL
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
COMPLETE
Integrity impact
COMPLETE
Availability impact
COMPLETE
local
low complexity
fedoraproject
gnome
CWE-264
nessus
NVD
Published: 2015-11-24
Updated: 2018-01-05

Summary

GNOME Display Manager (gdm) before 3.18.2 allows physically proximate attackers to bypass the lock screen by holding the Escape key.

Vulnerable Configurations

Part Description Count
OS
Fedoraproject
1
Application
Gnome
202

Common Weakness Enumeration (CWE)

Common Attack Pattern Enumeration and Classification (CAPEC)

  • 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.
  • Blue Boxing
    This type of attack against older telephone switches and trunks has been around for decades. A tone is sent by an adversary to impersonate a supervisor signal which has the effect of rerouting or usurping command of the line. While the US infrastructure proper may not contain widespread vulnerabilities to this type of attack, many companies are connected globally through call centers and business process outsourcing. These international systems may be operated in countries which have not upgraded Telco infrastructure and so are vulnerable to Blue boxing. Blue boxing is a result of failure on the part of the system to enforce strong authorization for administrative functions. While the infrastructure is different than standard current applications like web applications, there are historical lessons to be learned to upgrade the access control for administrative functions.
  • Restful Privilege Elevation
    Rest uses standard HTTP (Get, Put, Delete) style permissions methods, but these are not necessarily correlated generally with back end programs. Strict interpretation of HTTP get methods means that these HTTP Get services should not be used to delete information on the server, but there is no access control mechanism to back up this logic. This means that unless the services are properly ACL'd and the application's service implementation are following these guidelines then an HTTP request can easily execute a delete or update on the server side. The attacker identifies a HTTP Get URL such as http://victimsite/updateOrder, which calls out to a program to update orders on a database or other resource. The URL is not idempotent so the request can be submitted multiple times by the attacker, additionally, the attacker may be able to exploit the URL published as a Get method that actually performs updates (instead of merely retrieving data). This may result in malicious or inadvertent altering of data on the server.
  • Target Programs with Elevated Privileges
    This attack targets programs running with elevated privileges. The attacker would try to leverage a bug in the running program and get arbitrary code to execute with elevated privileges. For instance an attacker would look for programs that write to the system directories or registry keys (such as HKLM, which stores a number of critical Windows environment variables). These programs are typically running with elevated privileges and have usually not been designed with security in mind. Such programs are excellent exploit targets because they yield lots of power when they break. The malicious user try to execute its code at the same level as a privileged system call.

Nessus

  • NASL familyRed Hat Local Security Checks
    NASL idREDHAT-RHSA-2017-2128.NASL
    descriptionAn update for gdm and gnome-session is now available for Red Hat Enterprise Linux 7. Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section. The GNOME Display Manager (GDM) provides the graphical login screen shown shortly after boot up, log out, and when user-switching. The following packages have been upgraded to a later upstream version: gdm (3.22.3), gnome-session (3.22.3). (BZ#1386862, BZ#1386957) Security Fix(es) : * It was found that gdm could crash due to a signal handler dispatched to an invalid conversation. An attacker could crash gdm by holding the escape key when the screen is locked, possibly bypassing the locked screen. (CVE-2015-7496) Additional Changes : For detailed information on changes in this release, see the Red Hat Enterprise Linux 7.4 Release Notes linked from the References section.
    last seen2020-06-01
    modified2020-06-02
    plugin id102113
    published2017-08-02
    reporterThis script is Copyright (C) 2017-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/102113
    titleRHEL 7 : gdm and gnome-session (RHSA-2017:2128)
    code
    #
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were  
# extracted from Red Hat Security Advisory RHSA-2017:2128. The text 
# itself is copyright (C) Red Hat, Inc.
#

include("compat.inc");

if (description)
{
  script_id(102113);
  script_version("3.11");
  script_cvs_date("Date: 2019/10/24 15:35:43");

  script_cve_id("CVE-2015-7496");
  script_xref(name:"RHSA", value:"2017:2128");

  script_name(english:"RHEL 7 : gdm and gnome-session (RHSA-2017:2128)");
  script_summary(english:"Checks the rpm output for the updated packages");

  script_set_attribute(
    attribute:"synopsis", 
    value:"The remote Red Hat host is missing one or more security updates."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"An update for gdm and gnome-session is now available for Red Hat
Enterprise Linux 7.

Red Hat Product Security has rated this update as having a security
impact of Moderate. A Common Vulnerability Scoring System (CVSS) base
score, which gives a detailed severity rating, is available for each
vulnerability from the CVE link(s) in the References section.

The GNOME Display Manager (GDM) provides the graphical login screen
shown shortly after boot up, log out, and when user-switching.

The following packages have been upgraded to a later upstream version:
gdm (3.22.3), gnome-session (3.22.3). (BZ#1386862, BZ#1386957)

Security Fix(es) :

* It was found that gdm could crash due to a signal handler dispatched
to an invalid conversation. An attacker could crash gdm by holding the
escape key when the screen is locked, possibly bypassing the locked
screen. (CVE-2015-7496)

Additional Changes :

For detailed information on changes in this release, see the Red Hat
Enterprise Linux 7.4 Release Notes linked from the References section."
  );
  # https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/
  script_set_attribute(
    attribute:"see_also",
    value:"http://www.nessus.org/u?3395ff0b"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://access.redhat.com/errata/RHSA-2017:2128"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://access.redhat.com/security/cve/cve-2015-7496"
  );
  script_set_attribute(attribute:"solution", value:"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:U/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:redhat:enterprise_linux:gdm");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:gdm-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:gdm-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:gnome-session");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:gnome-session-custom-session");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:gnome-session-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:gnome-session-xsession");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:redhat:enterprise_linux:7");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:redhat:enterprise_linux:7.4");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:redhat:enterprise_linux:7.5");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:redhat:enterprise_linux:7.6");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:redhat:enterprise_linux:7.7");

  script_set_attribute(attribute:"vuln_publication_date", value:"2015/11/24");
  script_set_attribute(attribute:"patch_publication_date", value:"2017/08/01");
  script_set_attribute(attribute:"plugin_publication_date", value:"2017/08/02");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2017-2019 and is owned by Tenable, Inc. or an Affiliate thereof.");
  script_family(english:"Red Hat Local Security Checks");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/RedHat/release", "Host/RedHat/rpm-list", "Host/cpu");

  exit(0);
}


include("audit.inc");
include("global_settings.inc");
include("misc_func.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) || "Red Hat" >!< release) audit(AUDIT_OS_NOT, "Red Hat");
os_ver = pregmatch(pattern: "Red Hat Enterprise Linux.*release ([0-9]+(\.[0-9]+)?)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "Red Hat");
os_ver = os_ver[1];
if (! preg(pattern:"^7([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, "Red Hat 7.x", "Red Hat " + 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$" && "s390" >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, "Red Hat", cpu);

yum_updateinfo = get_kb_item("Host/RedHat/yum-updateinfo");
if (!empty_or_null(yum_updateinfo)) 
{
  rhsa = "RHSA-2017:2128";
  yum_report = redhat_generate_yum_updateinfo_report(rhsa:rhsa);
  if (!empty_or_null(yum_report))
  {
    security_report_v4(
      port       : 0,
      severity   : SECURITY_HOLE,
      extra      : yum_report 
    );
    exit(0);
  }
  else
  {
    audit_message = "affected by Red Hat security advisory " + rhsa;
    audit(AUDIT_OS_NOT, audit_message);
  }
}
else
{
  flag = 0;
  if (rpm_check(release:"RHEL7", reference:"gdm-3.22.3-11.el7")) flag++;

  if (rpm_check(release:"RHEL7", reference:"gdm-debuginfo-3.22.3-11.el7")) flag++;

  if (rpm_check(release:"RHEL7", reference:"gdm-devel-3.22.3-11.el7")) flag++;

  if (rpm_check(release:"RHEL7", cpu:"s390x", reference:"gnome-session-3.22.3-4.el7")) flag++;

  if (rpm_check(release:"RHEL7", cpu:"x86_64", reference:"gnome-session-3.22.3-4.el7")) flag++;

  if (rpm_check(release:"RHEL7", cpu:"s390x", reference:"gnome-session-custom-session-3.22.3-4.el7")) flag++;

  if (rpm_check(release:"RHEL7", cpu:"x86_64", reference:"gnome-session-custom-session-3.22.3-4.el7")) flag++;

  if (rpm_check(release:"RHEL7", cpu:"s390x", reference:"gnome-session-debuginfo-3.22.3-4.el7")) flag++;

  if (rpm_check(release:"RHEL7", cpu:"x86_64", reference:"gnome-session-debuginfo-3.22.3-4.el7")) flag++;

  if (rpm_check(release:"RHEL7", cpu:"s390x", reference:"gnome-session-xsession-3.22.3-4.el7")) flag++;

  if (rpm_check(release:"RHEL7", cpu:"x86_64", reference:"gnome-session-xsession-3.22.3-4.el7")) flag++;


  if (flag)
  {
    security_report_v4(
      port       : 0,
      severity   : SECURITY_HOLE,
      extra      : rpm_report_get() + redhat_report_package_caveat()
    );
    exit(0);
  }
  else
  {
    tested = pkg_tests_get();
    if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
    else audit(AUDIT_PACKAGE_NOT_INSTALLED, "gdm / gdm-debuginfo / gdm-devel / gnome-session / etc");
  }
}
  • NASL familyHuawei Local Security Checks
    NASL idEULEROS_SA-2017-1174.NASL
    descriptionAccording to the version of the gdm package installed, the EulerOS installation on the remote host is affected by the following vulnerability : - It was found that gdm could crash due to a signal handler dispatched to an invalid conversation. An attacker could crash gdm by holding the escape key when the screen is locked, possibly bypassing the locked screen. (CVE-2015-7496) Note that Tenable Network Security has extracted the preceding description block directly from the EulerOS security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
    last seen2020-05-06
    modified2017-09-08
    plugin id103012
    published2017-09-08
    reporterThis script is Copyright (C) 2017-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/103012
    titleEulerOS 2.0 SP2 : gdm (EulerOS-SA-2017-1174)
    code
    #
# (C) Tenable Network Security, Inc.
#

include("compat.inc");

if (description)
{
  script_id(103012);
  script_version("3.10");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/05/04");

  script_cve_id(
    "CVE-2015-7496"
  );

  script_name(english:"EulerOS 2.0 SP2 : gdm (EulerOS-SA-2017-1174)");
  script_summary(english:"Checks the rpm output for the updated package.");

  script_set_attribute(attribute:"synopsis", value:
"The remote EulerOS host is missing a security update.");
  script_set_attribute(attribute:"description", value:
"According to the version of the gdm package installed, the EulerOS
installation on the remote host is affected by the following
vulnerability :

  - It was found that gdm could crash due to a signal
    handler dispatched to an invalid conversation. An
    attacker could crash gdm by holding the escape key when
    the screen is locked, possibly bypassing the locked
    screen. (CVE-2015-7496)

Note that Tenable Network Security has extracted the preceding
description block directly from the EulerOS security advisory. Tenable
has attempted to automatically clean and format it as much as possible
without introducing additional issues.");
  # https://developer.huaweicloud.com/ict/en/site-euleros/euleros/security-advisories/EulerOS-SA-2017-1174
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?a908e0e6");
  script_set_attribute(attribute:"solution", value:
"Update the affected gdm package.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");

  script_set_attribute(attribute:"patch_publication_date", value:"2017/08/16");
  script_set_attribute(attribute:"plugin_publication_date", value:"2017/09/08");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:huawei:euleros:gdm");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:huawei:euleros:2.0");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Huawei Local Security Checks");

  script_copyright(english:"This script is Copyright (C) 2017-2020 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/EulerOS/release", "Host/EulerOS/rpm-list", "Host/EulerOS/sp");
  script_exclude_keys("Host/EulerOS/uvp_version");

  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/EulerOS/release");
if (isnull(release) || release !~ "^EulerOS") audit(AUDIT_OS_NOT, "EulerOS");
if (release !~ "^EulerOS release 2\.0(\D|$)") audit(AUDIT_OS_NOT, "EulerOS 2.0");

sp = get_kb_item("Host/EulerOS/sp");
if (isnull(sp) || sp !~ "^(2)$") audit(AUDIT_OS_NOT, "EulerOS 2.0 SP2");

uvp = get_kb_item("Host/EulerOS/uvp_version");
if (!empty_or_null(uvp)) audit(AUDIT_OS_NOT, "EulerOS 2.0 SP2", "EulerOS UVP " + uvp);

if (!get_kb_item("Host/EulerOS/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$" && "aarch64" >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, "EulerOS", cpu);
if ("x86_64" >!< cpu && cpu !~ "^i[3-6]86$") audit(AUDIT_ARCH_NOT, "i686 / x86_64", cpu);

flag = 0;

pkgs = ["gdm-3.14.2-12.h1"];

foreach (pkg in pkgs)
  if (rpm_check(release:"EulerOS-2.0", sp:"2", reference:pkg)) flag++;

if (flag)
{
  security_report_v4(
    port       : 0,
    severity   : SECURITY_HOLE,
    extra      : rpm_report_get()
  );
  exit(0);
}
else
{
  tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, "gdm");
}
  • NASL familyScientific Linux Local Security Checks
    NASL idSL_20170802_GDM_AND_GNOME_SESSION_ON_SL7_X.NASL
    descriptionThe following packages have been upgraded to a later upstream version: gdm (3.22.3), gnome-session (3.22.3). Security Fix(es) : - It was found that gdm could crash due to a signal handler dispatched to an invalid conversation. An attacker could crash gdm by holding the escape key when the screen is locked, possibly bypassing the locked screen. (CVE-2015-7496)
    last seen2020-03-18
    modified2017-08-22
    plugin id102662
    published2017-08-22
    reporterThis script is Copyright (C) 2017-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/102662
    titleScientific Linux Security Update : gdm and gnome-session on SL7.x x86_64 (20170802)
    code
    #
# (C) Tenable Network Security, Inc.
#
# The descriptive text is (C) Scientific Linux.
#

include("compat.inc");

if (description)
{
  script_id(102662);
  script_version("3.3");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/02/25");

  script_cve_id("CVE-2015-7496");

  script_name(english:"Scientific Linux Security Update : gdm and gnome-session on SL7.x x86_64 (20170802)");
  script_summary(english:"Checks rpm output for the updated packages");

  script_set_attribute(
    attribute:"synopsis", 
    value:
"The remote Scientific Linux host is missing one or more security
updates."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"The following packages have been upgraded to a later upstream version:
gdm (3.22.3), gnome-session (3.22.3).

Security Fix(es) :

  - It was found that gdm could crash due to a signal
    handler dispatched to an invalid conversation. An
    attacker could crash gdm by holding the escape key when
    the screen is locked, possibly bypassing the locked
    screen. (CVE-2015-7496)"
  );
  # https://listserv.fnal.gov/scripts/wa.exe?A2=ind1708&L=scientific-linux-errata&F=&S=&P=6394
  script_set_attribute(
    attribute:"see_also",
    value:"http://www.nessus.org/u?906071d0"
  );
  script_set_attribute(attribute:"solution", value:"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/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:fermilab:scientific_linux:gdm");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fermilab:scientific_linux:gdm-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fermilab:scientific_linux:gdm-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fermilab:scientific_linux:gnome-session");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fermilab:scientific_linux:gnome-session-custom-session");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fermilab:scientific_linux:gnome-session-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fermilab:scientific_linux:gnome-session-xsession");
  script_set_attribute(attribute:"cpe", value:"x-cpe:/o:fermilab:scientific_linux");

  script_set_attribute(attribute:"vuln_publication_date", value:"2015/11/24");
  script_set_attribute(attribute:"patch_publication_date", value:"2017/08/02");
  script_set_attribute(attribute:"plugin_publication_date", value:"2017/08/22");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2017-2020 and is owned by Tenable, Inc. or an Affiliate thereof.");
  script_family(english:"Scientific Linux Local Security Checks");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/cpu", "Host/RedHat/release", "Host/RedHat/rpm-list");

  exit(0);
}


include("audit.inc");
include("global_settings.inc");
include("misc_func.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) || "Scientific Linux " >!< release) audit(AUDIT_HOST_NOT, "running Scientific Linux");
os_ver = pregmatch(pattern: "Scientific Linux.*release ([0-9]+(\.[0-9]+)?)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "Scientific Linux");
os_ver = os_ver[1];
if (! preg(pattern:"^7([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, "Scientific Linux 7.x", "Scientific Linux " + 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 (cpu >!< "x86_64" && cpu !~ "^i[3-6]86$") audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, "Scientific Linux", cpu);
if ("x86_64" >!< cpu) audit(AUDIT_ARCH_NOT, "x86_64", cpu);


flag = 0;
if (rpm_check(release:"SL7", cpu:"x86_64", reference:"gdm-3.22.3-11.el7")) flag++;
if (rpm_check(release:"SL7", cpu:"x86_64", reference:"gdm-debuginfo-3.22.3-11.el7")) flag++;
if (rpm_check(release:"SL7", cpu:"x86_64", reference:"gdm-devel-3.22.3-11.el7")) flag++;
if (rpm_check(release:"SL7", cpu:"x86_64", reference:"gnome-session-3.22.3-4.el7")) flag++;
if (rpm_check(release:"SL7", cpu:"x86_64", reference:"gnome-session-custom-session-3.22.3-4.el7")) flag++;
if (rpm_check(release:"SL7", cpu:"x86_64", reference:"gnome-session-debuginfo-3.22.3-4.el7")) flag++;
if (rpm_check(release:"SL7", cpu:"x86_64", reference:"gnome-session-xsession-3.22.3-4.el7")) flag++;


if (flag)
{
  security_report_v4(
    port       : 0,
    severity   : SECURITY_HOLE,
    extra      : rpm_report_get()
  );
  exit(0);
}
else
{
  tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, "gdm / gdm-debuginfo / gdm-devel / gnome-session / etc");
}
  • NASL familyCentOS Local Security Checks
    NASL idCENTOS_RHSA-2017-2128.NASL
    descriptionAn update for gdm and gnome-session is now available for Red Hat Enterprise Linux 7. Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section. The GNOME Display Manager (GDM) provides the graphical login screen shown shortly after boot up, log out, and when user-switching. The following packages have been upgraded to a later upstream version: gdm (3.22.3), gnome-session (3.22.3). (BZ#1386862, BZ#1386957) Security Fix(es) : * It was found that gdm could crash due to a signal handler dispatched to an invalid conversation. An attacker could crash gdm by holding the escape key when the screen is locked, possibly bypassing the locked screen. (CVE-2015-7496) Additional Changes : For detailed information on changes in this release, see the Red Hat Enterprise Linux 7.4 Release Notes linked from the References section.
    last seen2020-06-01
    modified2020-06-02
    plugin id102753
    published2017-08-25
    reporterThis script is Copyright (C) 2017-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/102753
    titleCentOS 7 : gdm / gnome-session (CESA-2017:2128)
    code
    #
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were  
# extracted from Red Hat Security Advisory RHSA-2017:2128 and 
# CentOS Errata and Security Advisory 2017:2128 respectively.
#

include("compat.inc");

if (description)
{
  script_id(102753);
  script_version("3.5");
  script_cvs_date("Date: 2019/12/31");

  script_cve_id("CVE-2015-7496");
  script_xref(name:"RHSA", value:"2017:2128");

  script_name(english:"CentOS 7 : gdm / gnome-session (CESA-2017:2128)");
  script_summary(english:"Checks rpm output for the updated packages");

  script_set_attribute(
    attribute:"synopsis", 
    value:"The remote CentOS host is missing one or more security updates."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"An update for gdm and gnome-session is now available for Red Hat
Enterprise Linux 7.

Red Hat Product Security has rated this update as having a security
impact of Moderate. A Common Vulnerability Scoring System (CVSS) base
score, which gives a detailed severity rating, is available for each
vulnerability from the CVE link(s) in the References section.

The GNOME Display Manager (GDM) provides the graphical login screen
shown shortly after boot up, log out, and when user-switching.

The following packages have been upgraded to a later upstream version:
gdm (3.22.3), gnome-session (3.22.3). (BZ#1386862, BZ#1386957)

Security Fix(es) :

* It was found that gdm could crash due to a signal handler dispatched
to an invalid conversation. An attacker could crash gdm by holding the
escape key when the screen is locked, possibly bypassing the locked
screen. (CVE-2015-7496)

Additional Changes :

For detailed information on changes in this release, see the Red Hat
Enterprise Linux 7.4 Release Notes linked from the References section."
  );
  # https://lists.centos.org/pipermail/centos-cr-announce/2017-August/004125.html
  script_set_attribute(
    attribute:"see_also",
    value:"http://www.nessus.org/u?9204a2aa"
  );
  # https://lists.centos.org/pipermail/centos-cr-announce/2017-August/004164.html
  script_set_attribute(
    attribute:"see_also",
    value:"http://www.nessus.org/u?898211ad"
  );
  script_set_attribute(
    attribute:"solution", 
    value:"Update the affected gdm and / or gnome-session packages."
  );
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2015-7496");
  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:centos:centos:gdm");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:gdm-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:gnome-session");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:gnome-session-custom-session");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:gnome-session-xsession");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:centos:centos:7");

  script_set_attribute(attribute:"vuln_publication_date", value:"2015/11/24");
  script_set_attribute(attribute:"patch_publication_date", value:"2017/08/23");
  script_set_attribute(attribute:"plugin_publication_date", value:"2017/08/25");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2017-2019 and is owned by Tenable, Inc. or an Affiliate thereof.");
  script_family(english:"CentOS Local Security Checks");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/CentOS/release", "Host/CentOS/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/CentOS/release");
if (isnull(release) || "CentOS" >!< release) audit(AUDIT_OS_NOT, "CentOS");
os_ver = pregmatch(pattern: "CentOS(?: Linux)? release ([0-9]+)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "CentOS");
os_ver = os_ver[1];
if (! preg(pattern:"^7([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, "CentOS 7.x", "CentOS " + os_ver);

if (!get_kb_item("Host/CentOS/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, "CentOS", cpu);


flag = 0;
if (rpm_check(release:"CentOS-7", cpu:"x86_64", reference:"gdm-3.22.3-11.el7")) flag++;
if (rpm_check(release:"CentOS-7", cpu:"x86_64", reference:"gdm-devel-3.22.3-11.el7")) flag++;
if (rpm_check(release:"CentOS-7", cpu:"x86_64", reference:"gnome-session-3.22.3-4.el7")) flag++;
if (rpm_check(release:"CentOS-7", cpu:"x86_64", reference:"gnome-session-custom-session-3.22.3-4.el7")) flag++;
if (rpm_check(release:"CentOS-7", cpu:"x86_64", reference:"gnome-session-xsession-3.22.3-4.el7")) flag++;


if (flag)
{
  cr_plugin_caveat = '\n' +
    'NOTE: The security advisory associated with this vulnerability has a\n' +
    'fixed package version that may only be available in the continuous\n' +
    'release (CR) repository for CentOS, until it is present in the next\n' +
    'point release of CentOS.\n\n' +

    'If an equal or higher package level does not exist in the baseline\n' +
    'repository for your major version of CentOS, then updates from the CR\n' +
    'repository will need to be applied in order to address the\n' +
    'vulnerability.\n';
  security_report_v4(
    port       : 0,
    severity   : SECURITY_HOLE,
    extra      : rpm_report_get() + cr_plugin_caveat
  );
  exit(0);
}
else
{
  tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, "gdm / gdm-devel / gnome-session / gnome-session-custom-session / etc");
}
  • NASL familyHuawei Local Security Checks
    NASL idEULEROS_SA-2017-1173.NASL
    descriptionAccording to the version of the gdm packages installed, the EulerOS installation on the remote host is affected by the following vulnerability : - It was found that gdm could crash due to a signal handler dispatched to an invalid conversation. An attacker could crash gdm by holding the escape key when the screen is locked, possibly bypassing the locked screen. (CVE-2015-7496) Note that Tenable Network Security has extracted the preceding description block directly from the EulerOS security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
    last seen2020-05-06
    modified2017-09-08
    plugin id103011
    published2017-09-08
    reporterThis script is Copyright (C) 2017-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/103011
    titleEulerOS 2.0 SP1 : gdm (EulerOS-SA-2017-1173)
  • NASL familyFedora Local Security Checks
    NASL idFEDORA_2015-271025C598.NASL
    descriptionThis update fixes CVE-2015-7496 - lock screen bypass when holding escape key. 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 seen2020-06-05
    modified2016-03-04
    plugin id89180
    published2016-03-04
    reporterThis script is Copyright (C) 2016-2020 Tenable Network Security, Inc.
    sourcehttps://www.tenable.com/plugins/nessus/89180
    titleFedora 23 : gdm-3.18.2-1.fc23 (2015-271025c598)
  • NASL familyFreeBSD Local Security Checks
    NASL idFREEBSD_PKG_68847B208DDC11E5B69CC86000169601.NASL
    descriptionRay Strode reports : CVE-2015-7496 - lock screen bypass when holding escape key.
    last seen2020-06-01
    modified2020-06-02
    plugin id86922
    published2015-11-19
    reporterThis script is Copyright (C) 2015-2018 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/86922
    titleFreeBSD : gdm -- lock screen bypass when holding escape key (68847b20-8ddc-11e5-b69c-c86000169601)
  • NASL familyOracle Linux Local Security Checks
    NASL idORACLELINUX_ELSA-2017-2128.NASL
    descriptionFrom Red Hat Security Advisory 2017:2128 : An update for gdm and gnome-session is now available for Red Hat Enterprise Linux 7. Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section. The GNOME Display Manager (GDM) provides the graphical login screen shown shortly after boot up, log out, and when user-switching. The following packages have been upgraded to a later upstream version: gdm (3.22.3), gnome-session (3.22.3). (BZ#1386862, BZ#1386957) Security Fix(es) : * It was found that gdm could crash due to a signal handler dispatched to an invalid conversation. An attacker could crash gdm by holding the escape key when the screen is locked, possibly bypassing the locked screen. (CVE-2015-7496) Additional Changes : For detailed information on changes in this release, see the Red Hat Enterprise Linux 7.4 Release Notes linked from the References section.
    last seen2020-06-01
    modified2020-06-02
    plugin id102297
    published2017-08-09
    reporterThis script is Copyright (C) 2017-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/102297
    titleOracle Linux 7 : gdm / gnome-session (ELSA-2017-2128)

Redhat

advisories
bugzilla
id1449632
titleFuzzy translations in de, es, fr, it, ja, ko, pt_BR, ru, zh_CN, zh_TW
oval
OR
  • commentRed Hat Enterprise Linux must be installed
    ovaloval:com.redhat.rhba:tst:20070304026
  • AND
    • commentRed Hat Enterprise Linux 7 is installed
      ovaloval:com.redhat.rhba:tst:20150364027
    • OR
      • AND
        • commentgnome-session-custom-session is earlier than 0:3.22.3-4.el7
          ovaloval:com.redhat.rhsa:tst:20172128001
        • commentgnome-session-custom-session is signed with Red Hat redhatrelease2 key
          ovaloval:com.redhat.rhba:tst:20192044068
      • AND
        • commentgnome-session-xsession is earlier than 0:3.22.3-4.el7
          ovaloval:com.redhat.rhsa:tst:20172128003
        • commentgnome-session-xsession is signed with Red Hat redhatrelease2 key
          ovaloval:com.redhat.rhba:tst:20192044064
      • AND
        • commentgnome-session is earlier than 0:3.22.3-4.el7
          ovaloval:com.redhat.rhsa:tst:20172128005
        • commentgnome-session is signed with Red Hat redhatrelease2 key
          ovaloval:com.redhat.rhba:tst:20192044062
      • AND
        • commentgdm-devel is earlier than 1:3.22.3-11.el7
          ovaloval:com.redhat.rhsa:tst:20172128007
        • commentgdm-devel is signed with Red Hat redhatrelease2 key
          ovaloval:com.redhat.rhsa:tst:20172128008
      • AND
        • commentgdm is earlier than 1:3.22.3-11.el7
          ovaloval:com.redhat.rhsa:tst:20172128009
        • commentgdm is signed with Red Hat redhatrelease2 key
          ovaloval:com.redhat.rhsa:tst:20110395006
rhsa
idRHSA-2017:2128
released2017-08-01
severityModerate
titleRHSA-2017:2128: gdm and gnome-session security, bug fix, and enhancement update (Moderate)
rpms
  • gdm-1:3.22.3-11.el7
  • gdm-debuginfo-1:3.22.3-11.el7
  • gdm-devel-1:3.22.3-11.el7
  • gnome-session-0:3.22.3-4.el7
  • gnome-session-custom-session-0:3.22.3-4.el7
  • gnome-session-debuginfo-0:3.22.3-4.el7
  • gnome-session-xsession-0:3.22.3-4.el7

References