Vulnerabilities > CVE-2019-12209 - Link Following vulnerability in Yubico Pam-U2F 1.0.7

047910
CVSS 7.5 - HIGH
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
HIGH
Integrity impact
NONE
Availability impact
NONE
network
low complexity
yubico
CWE-59
nessus
NVD
Published: 2019-06-04
Updated: 2024-11-21

Summary

Yubico pam-u2f 1.0.7 attempts parsing of the configured authfile (default $HOME/.config/Yubico/u2f_keys) as root (unless openasuser was enabled), and does not properly verify that the path lacks symlinks pointing to other files on the system owned by root. If the debug option is enabled in the PAM configuration, part of the file contents of a symlink target will be logged, possibly revealing sensitive information.

Vulnerable Configurations

Part Description Count
Application
Yubico
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_2019-B6D3C8B0A8.NASL
    descriptionNew upstream release Fixes Debug file descriptor leak CVE-2019-1221 Fixes insecure debug file handling CVE-2019-1220 Note that Tenable Network Security has extracted the preceding description block directly from the Fedora update system website. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
    last seen2020-06-01
    modified2020-06-02
    plugin id126056
    published2019-06-20
    reporterThis script is Copyright (C) 2019-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/126056
    titleFedora 30 : pam-u2f (2019-b6d3c8b0a8)
    code
    #
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were  
# extracted from Fedora Security Advisory FEDORA-2019-b6d3c8b0a8.
#

include("compat.inc");

if (description)
{
  script_id(126056);
  script_version("1.6");
  script_cvs_date("Date: 2020/02/12");

  script_cve_id("CVE-2019-1220", "CVE-2019-12209", "CVE-2019-1221");
  script_xref(name:"FEDORA", value:"2019-b6d3c8b0a8");

  script_name(english:"Fedora 30 : pam-u2f (2019-b6d3c8b0a8)");
  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:
"New upstream release Fixes Debug file descriptor leak CVE-2019-1221
Fixes insecure debug file handling CVE-2019-1220

Note that Tenable Network Security has extracted the preceding
description block directly from the Fedora update system website.
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://bodhi.fedoraproject.org/updates/FEDORA-2019-b6d3c8b0a8"
  );
  script_set_attribute(
    attribute:"solution", 
    value:"Update the affected pam-u2f package."
  );
  script_set_cvss_base_vector("CVSS2#AV:N/AC:H/Au:N/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:H/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:H/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2019-1221");
  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");
  script_set_attribute(attribute:"exploited_by_malware", value:"true");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fedoraproject:fedora:pam-u2f");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:fedoraproject:fedora:30");

  script_set_attribute(attribute:"vuln_publication_date", value:"2019/06/04");
  script_set_attribute(attribute:"patch_publication_date", value:"2019/06/19");
  script_set_attribute(attribute:"plugin_publication_date", value:"2019/06/20");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2019-2020 and is owned by Tenable, Inc. or an Affiliate thereof.");
  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 = pregmatch(pattern: "Fedora.*release ([0-9]+)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "Fedora");
os_ver = os_ver[1];
if (! preg(pattern:"^30([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, "Fedora 30", "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:"FC30", reference:"pam-u2f-1.0.8-1.fc30")) 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, "pam-u2f");
}
  • NASL familySuSE Local Security Checks
    NASL idSUSE_SU-2019-1749-1.NASL
    descriptionThis update for libu2f-host and pam_u2f to version 1.0.8 fixes the following issues : Security issues fixed for libu2f-host : CVE-2019-9578: Fixed a memory leak due to a wrong parse of init
    last seen2020-06-01
    modified2020-06-02
    plugin id126501
    published2019-07-05
    reporterThis script is Copyright (C) 2019-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/126501
    titleSUSE SLED12 / SLES12 Security Update : libu2f-host (SUSE-SU-2019:1749-1)
    code
    #
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from SUSE update advisory SUSE-SU-2019:1749-1.
# The text itself is copyright (C) SUSE.
#

include("compat.inc");

if (description)
{
  script_id(126501);
  script_version("1.3");
  script_cvs_date("Date: 2020/01/08");

  script_cve_id("CVE-2018-20340", "CVE-2019-12209", "CVE-2019-12210", "CVE-2019-9578");

  script_name(english:"SUSE SLED12 / SLES12 Security Update : libu2f-host (SUSE-SU-2019:1749-1)");
  script_summary(english:"Checks rpm output for the updated packages.");

  script_set_attribute(
    attribute:"synopsis", 
    value:"The remote SUSE host is missing one or more security updates."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"This update for libu2f-host and pam_u2f to version 1.0.8 fixes the
following issues :

Security issues fixed for libu2f-host :

CVE-2019-9578: Fixed a memory leak due to a wrong parse of init's
response (bsc#1128140).

CVE-2018-20340: Fixed an unchecked buffer, which could allow a buffer
overflow with a custom made malicious USB device (bsc#1124781).

Security issues fixed for pam_u2f: CVE-2019-12209: Fixed an issue
where symlinks in the user's directory were followed (bsc#1135729).

CVE-2019-12210: Fixed file descriptor leaks (bsc#1135727).

Note that Tenable Network Security has extracted the preceding
description block directly from the SUSE 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.suse.com/show_bug.cgi?id=1124781"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bugzilla.suse.com/show_bug.cgi?id=1128140"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bugzilla.suse.com/show_bug.cgi?id=1135727"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bugzilla.suse.com/show_bug.cgi?id=1135729"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://www.suse.com/security/cve/CVE-2018-20340/"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://www.suse.com/security/cve/CVE-2019-12209/"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://www.suse.com/security/cve/CVE-2019-12210/"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://www.suse.com/security/cve/CVE-2019-9578/"
  );
  # https://www.suse.com/support/update/announcement/2019/suse-su-20191749-1/
  script_set_attribute(
    attribute:"see_also",
    value:"http://www.nessus.org/u?61def403"
  );
  script_set_attribute(
    attribute:"solution", 
    value:
"To install this SUSE Security Update use the SUSE recommended
installation methods like YaST online_update or 'zypper patch'.

Alternatively you can run the command listed for your product :

SUSE Linux Enterprise Server 12-SP4:zypper in -t patch
SUSE-SLE-SERVER-12-SP4-2019-1749=1

SUSE Linux Enterprise Desktop 12-SP4:zypper in -t patch
SUSE-SLE-DESKTOP-12-SP4-2019-1749=1"
  );
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:S/C:P/I:P/A:N");
  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:L/UI:N/S:U/C:H/I:H/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:suse_linux:libu2f-host-debugsource");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:suse_linux:libu2f-host0");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:suse_linux:libu2f-host0-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:suse_linux:pam_u2f");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:suse_linux:pam_u2f-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:suse_linux:pam_u2f-debugsource");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:novell:suse_linux:12");

  script_set_attribute(attribute:"vuln_publication_date", value:"2019/03/05");
  script_set_attribute(attribute:"patch_publication_date", value:"2019/07/04");
  script_set_attribute(attribute:"plugin_publication_date", value:"2019/07/05");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2019-2020 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/cpu", "Host/SuSE/release", "Host/SuSE/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/SuSE/release");
if (isnull(release) || release !~ "^(SLED|SLES)") audit(AUDIT_OS_NOT, "SUSE");
os_ver = pregmatch(pattern: "^(SLE(S|D)\d+)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "SUSE");
os_ver = os_ver[1];
if (! preg(pattern:"^(SLED12|SLES12)$", string:os_ver)) audit(AUDIT_OS_NOT, "SUSE SLED12 / SLES12", "SUSE " + os_ver);

if (!get_kb_item("Host/SuSE/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);

cpu = get_kb_item("Host/cpu");
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if (cpu !~ "^i[3-6]86$" && "x86_64" >!< cpu && "s390x" >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, "SUSE " + os_ver, cpu);

sp = get_kb_item("Host/SuSE/patchlevel");
if (isnull(sp)) sp = "0";
if (os_ver == "SLES12" && (! preg(pattern:"^(4)$", string:sp))) audit(AUDIT_OS_NOT, "SLES12 SP4", os_ver + " SP" + sp);
if (os_ver == "SLED12" && (! preg(pattern:"^(4)$", string:sp))) audit(AUDIT_OS_NOT, "SLED12 SP4", os_ver + " SP" + sp);


flag = 0;
if (rpm_check(release:"SLES12", sp:"4", reference:"libu2f-host-debugsource-1.1.6-3.5.1")) flag++;
if (rpm_check(release:"SLES12", sp:"4", reference:"libu2f-host0-1.1.6-3.5.1")) flag++;
if (rpm_check(release:"SLES12", sp:"4", reference:"libu2f-host0-debuginfo-1.1.6-3.5.1")) flag++;
if (rpm_check(release:"SLES12", sp:"4", reference:"pam_u2f-1.0.8-3.3.1")) flag++;
if (rpm_check(release:"SLES12", sp:"4", reference:"pam_u2f-debuginfo-1.0.8-3.3.1")) flag++;
if (rpm_check(release:"SLES12", sp:"4", reference:"pam_u2f-debugsource-1.0.8-3.3.1")) flag++;
if (rpm_check(release:"SLED12", sp:"4", cpu:"x86_64", reference:"libu2f-host-debugsource-1.1.6-3.5.1")) flag++;
if (rpm_check(release:"SLED12", sp:"4", cpu:"x86_64", reference:"libu2f-host0-1.1.6-3.5.1")) flag++;
if (rpm_check(release:"SLED12", sp:"4", cpu:"x86_64", reference:"libu2f-host0-debuginfo-1.1.6-3.5.1")) flag++;
if (rpm_check(release:"SLED12", sp:"4", cpu:"x86_64", reference:"pam_u2f-1.0.8-3.3.1")) flag++;
if (rpm_check(release:"SLED12", sp:"4", cpu:"x86_64", reference:"pam_u2f-debuginfo-1.0.8-3.3.1")) flag++;
if (rpm_check(release:"SLED12", sp:"4", cpu:"x86_64", reference:"pam_u2f-debugsource-1.0.8-3.3.1")) 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, "libu2f-host");
}
  • NASL familySuSE Local Security Checks
    NASL idOPENSUSE-2019-1708.NASL
    descriptionThis update for libu2f-host and pam_u2f to version 1.0.8 fixes the following issues : Security issues fixed for libu2f-host : - CVE-2019-9578: Fixed a memory leak due to a wrong parse of init
    last seen2020-06-01
    modified2020-06-02
    plugin id126883
    published2019-07-22
    reporterThis script is Copyright (C) 2019-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/126883
    titleopenSUSE Security Update : libu2f-host / pam_u2f (openSUSE-2019-1708)
  • NASL familySuSE Local Security Checks
    NASL idSUSE_SU-2019-1750-1.NASL
    descriptionThis update for libu2f-host and pam_u2f to version 1.0.8 fixes the following issues : Security issues fixed for libu2f-host : CVE-2019-9578: Fixed a memory leak due to a wrong parse of init
    last seen2020-06-01
    modified2020-06-02
    plugin id126502
    published2019-07-05
    reporterThis script is Copyright (C) 2019-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/126502
    titleSUSE SLED15 / SLES15 Security Update : libu2f-host, pam_u2f (SUSE-SU-2019:1750-1)
  • NASL familySuSE Local Security Checks
    NASL idOPENSUSE-2019-1725.NASL
    descriptionThis update for libu2f-host and pam_u2f to version 1.0.8 fixes the following issues : Security issues fixed for libu2f-host : - CVE-2019-9578: Fixed a memory leak due to a wrong parse of init
    last seen2020-06-01
    modified2020-06-02
    plugin id126889
    published2019-07-22
    reporterThis script is Copyright (C) 2019-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/126889
    titleopenSUSE Security Update : libu2f-host / pam_u2f (openSUSE-2019-1725)

References