Vulnerabilities > CVE-2017-16611 - Link Following vulnerability in multiple products
Attack vector
LOCAL Attack complexity
LOW Privileges required
LOW Confidentiality impact
NONE Integrity impact
NONE Availability impact
HIGH Summary
In libXfont before 1.5.4 and libXfont2 before 2.0.3, a local attacker can open (but not read) files on the system as root, triggering tape rewinds, watchdogs, or similar mechanisms that can be triggered by opening files.
Vulnerable Configurations
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 family Fedora Local Security Checks NASL id FEDORA_2018-05B078C373.NASL description Security fix for CVE-2017-16611 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 seen 2020-06-05 modified 2018-03-07 plugin id 107154 published 2018-03-07 reporter This script is Copyright (C) 2018-2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/107154 title Fedora 26 : libXfont2 (2018-05b078c373) 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 FEDORA-2018-05b078c373. # include("compat.inc"); if (description) { script_id(107154); script_version("1.3"); script_set_attribute(attribute:"plugin_modification_date", value:"2020/06/04"); script_cve_id("CVE-2017-16611"); script_xref(name:"FEDORA", value:"2018-05b078c373"); script_name(english:"Fedora 26 : libXfont2 (2018-05b078c373)"); 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: "Security fix for CVE-2017-16611 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-2018-05b078c373" ); script_set_attribute( attribute:"solution", value:"Update the affected libXfont2 package." ); script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:N/C:N/I:N/A:P"); script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"); script_set_attribute(attribute:"plugin_type", value:"local"); script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fedoraproject:fedora:libXfont2"); script_set_attribute(attribute:"cpe", value:"cpe:/o:fedoraproject:fedora:26"); script_set_attribute(attribute:"vuln_publication_date", value:"2017/12/01"); script_set_attribute(attribute:"patch_publication_date", value:"2018/03/06"); script_set_attribute(attribute:"plugin_publication_date", value:"2018/03/07"); script_set_attribute(attribute:"generated_plugin", value:"current"); script_end_attributes(); script_category(ACT_GATHER_INFO); script_copyright(english:"This script is Copyright (C) 2018-2020 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:"^26([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, "Fedora 26", "Fedora " + os_ver); if (!get_kb_item("Host/RedHat/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING); cpu = get_kb_item("Host/cpu"); if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH); if ("x86_64" >!< cpu && cpu !~ "^i[3-6]86$") audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, "Fedora", cpu); flag = 0; if (rpm_check(release:"FC26", reference:"libXfont2-2.0.3-1.fc26")) flag++; if (flag) { security_report_v4( port : 0, severity : SECURITY_NOTE, 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, "libXfont2"); }
NASL family Huawei Local Security Checks NASL id EULEROS_SA-2019-2625.NASL description According to the versions of the libXfont package installed, the EulerOS installation on the remote host is affected by the following vulnerabilities : - In libXfont before 1.5.4 and libXfont2 before 2.0.3, a local attacker can open (but not read) files on the system as root, triggering tape rewinds, watchdogs, or similar mechanisms that can be triggered by opening files.(CVE-2017-16611) - In the PatternMatch function in fontfile/fontdir.c in libXfont through 1.5.2 and 2.x before 2.0.2, an attacker with access to an X connection can cause a buffer over-read during pattern matching of fonts, leading to information disclosure or a crash (denial of service). This occurs because last seen 2020-05-08 modified 2019-12-18 plugin id 132160 published 2019-12-18 reporter This script is Copyright (C) 2019-2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/132160 title EulerOS 2.0 SP3 : libXfont (EulerOS-SA-2019-2625) NASL family Fedora Local Security Checks NASL id FEDORA_2018-4F5A3E792F.NASL description Security fix for CVE-2017-16611 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 seen 2020-06-05 modified 2018-03-07 plugin id 107164 published 2018-03-07 reporter This script is Copyright (C) 2018-2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/107164 title Fedora 27 : libXfont2 (2018-4f5a3e792f) NASL family Huawei Local Security Checks NASL id EULEROS_SA-2019-2357.NASL description According to the versions of the libXfont package installed, the EulerOS installation on the remote host is affected by the following vulnerabilities : - The LZW decompressor in (1) the BufCompressedFill function in fontfile/decompress.c in X.Org libXfont before 1.4.4 and (2) compress/compress.c in 4.3BSD, as used in zopen.c in OpenBSD before 3.8, FreeBSD, NetBSD 4.0.x and 5.0.x before 5.0.3 and 5.1.x before 5.1.1, FreeType 2.1.9, and other products, does not properly handle code words that are absent from the decompression table when encountered, which allows context-dependent attackers to trigger an infinite loop or a heap-based buffer overflow, and possibly execute arbitrary code, via a crafted compressed stream, a related issue to CVE-2006-1168 and CVE-2011-2896.(CVE-2011-2895) - In the pcfGetProperties function in bitmap/pcfread.c in libXfont through 1.5.2 and 2.x before 2.0.2, a missing boundary check (for PCF files) could be used by local attackers authenticated to an Xserver for a buffer over-read, for information disclosure or a crash of the X server.(CVE-2017-13722) - In the PatternMatch function in fontfile/fontdir.c in libXfont through 1.5.2 and 2.x before 2.0.2, an attacker with access to an X connection can cause a buffer over-read during pattern matching of fonts, leading to information disclosure or a crash (denial of service). This occurs because last seen 2020-05-08 modified 2019-12-10 plugin id 131849 published 2019-12-10 reporter This script is Copyright (C) 2019-2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/131849 title EulerOS 2.0 SP2 : libXfont (EulerOS-SA-2019-2357) NASL family Huawei Local Security Checks NASL id EULEROS_SA-2020-1459.NASL description According to the versions of the libXfont package installed, the EulerOS Virtualization installation on the remote host is affected by the following vulnerabilities : - In libXfont before 1.5.4 and libXfont2 before 2.0.3, a local attacker can open (but not read) files on the system as root, triggering tape rewinds, watchdogs, or similar mechanisms that can be triggered by opening files.(CVE-2017-16611) - In the pcfGetProperties function in bitmap/pcfread.c in libXfont through 1.5.2 and 2.x before 2.0.2, a missing boundary check (for PCF files) could be used by local attackers authenticated to an Xserver for a buffer over-read, for information disclosure or a crash of the X server.(CVE-2017-13722) - In the PatternMatch function in fontfile/fontdir.c in libXfont through 1.5.2 and 2.x before 2.0.2, an attacker with access to an X connection can cause a buffer over-read during pattern matching of fonts, leading to information disclosure or a crash (denial of service). This occurs because last seen 2020-04-30 modified 2020-04-16 plugin id 135621 published 2020-04-16 reporter This script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/135621 title EulerOS Virtualization 3.0.2.2 : libXfont (EulerOS-SA-2020-1459) NASL family FreeBSD Local Security Checks NASL id FREEBSD_PKG_08A125F3E35A11E7A29354E1AD3D6335.NASL description the freedesktop.org project reports : A non-privileged X client can instruct X server running under root to open any file by creating own directory with last seen 2020-06-01 modified 2020-06-02 plugin id 105335 published 2017-12-18 reporter This script is Copyright (C) 2017-2018 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/105335 title FreeBSD : libXfont -- permission bypass when opening files through symlinks (08a125f3-e35a-11e7-a293-54e1ad3d6335) NASL family Huawei Local Security Checks NASL id EULEROS_SA-2020-1241.NASL description According to the versions of the libXfont package installed, the EulerOS Virtualization for ARM 64 installation on the remote host is affected by the following vulnerabilities : - In libXfont before 1.5.4 and libXfont2 before 2.0.3, a local attacker can open (but not read) files on the system as root, triggering tape rewinds, watchdogs, or similar mechanisms that can be triggered by opening files.(CVE-2017-16611) - In the pcfGetProperties function in bitmap/pcfread.c in libXfont through 1.5.2 and 2.x before 2.0.2, a missing boundary check (for PCF files) could be used by local attackers authenticated to an Xserver for a buffer over-read, for information disclosure or a crash of the X server.(CVE-2017-13722) - In the PatternMatch function in fontfile/fontdir.c in libXfont through 1.5.2 and 2.x before 2.0.2, an attacker with access to an X connection can cause a buffer over-read during pattern matching of fonts, leading to information disclosure or a crash (denial of service). This occurs because last seen 2020-03-19 modified 2020-03-13 plugin id 134530 published 2020-03-13 reporter This script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/134530 title EulerOS Virtualization for ARM 64 3.0.2.0 : libXfont (EulerOS-SA-2020-1241) NASL family Slackware Local Security Checks NASL id SLACKWARE_SSA_2017-333-02.NASL description New libXfont packages are available for Slackware 13.0, 13.1, 13.37, 14.0, 14.1, and 14.2 to fix a security issue. last seen 2020-06-01 modified 2020-06-02 plugin id 104859 published 2017-11-30 reporter This script is Copyright (C) 2017-2018 Tenable Network Security, Inc. source https://www.tenable.com/plugins/nessus/104859 title Slackware 13.0 / 13.1 / 13.37 / 14.0 / 14.1 / 14.2 : libXfont (SSA:2017-333-02) NASL family Gentoo Local Security Checks NASL id GENTOO_GLSA-201801-10.NASL description The remote host is affected by the vulnerability described in GLSA-201801-10 (LibXfont, LibXfont2: Arbitrary file access) It was discovered that libXfont incorrectly followed symlinks when opening font files. Impact : A local unprivileged user could use this flaw to cause the X server to access arbitrary files, including special device files. Workaround : There is no known workaround at this time. last seen 2020-06-01 modified 2020-06-02 plugin id 105666 published 2018-01-09 reporter This script is Copyright (C) 2018-2019 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/105666 title GLSA-201801-10 : LibXfont, LibXfont2: Arbitrary file access NASL family Huawei Local Security Checks NASL id EULEROS_SA-2019-2172.NASL description According to the version of the libXfont package installed, the EulerOS installation on the remote host is affected by the following vulnerability : - In libXfont before 1.5.4 and libXfont2 before 2.0.3, a local attacker can open (but not read) files on the system as root, triggering tape rewinds, watchdogs, or similar mechanisms that can be triggered by opening files.(CVE-2017-16611) 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 seen 2020-05-08 modified 2019-11-12 plugin id 130881 published 2019-11-12 reporter This script is Copyright (C) 2019-2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/130881 title EulerOS 2.0 SP5 : libXfont (EulerOS-SA-2019-2172) NASL family Ubuntu Local Security Checks NASL id UBUNTU_USN-3500-1.NASL description It was discovered that libXfont incorrectly followed symlinks when opening font files. A local unprivileged user could use this issue to cause the X server to access arbitrary files, including special device files. Note that Tenable Network Security has extracted the preceding description block directly from the Ubuntu security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues. last seen 2020-06-01 modified 2020-06-02 plugin id 104883 published 2017-11-30 reporter Ubuntu Security Notice (C) 2017-2019 Canonical, Inc. / NASL script (C) 2017-2019 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/104883 title Ubuntu 14.04 LTS / 16.04 LTS / 17.04 / 17.10 : libxfont, libxfont1, libxfont2 vulnerability (USN-3500-1) NASL family Fedora Local Security Checks NASL id FEDORA_2018-5A7CD68500.NASL description Security fix for CVE-2017-16611 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 seen 2020-06-05 modified 2018-03-07 plugin id 107167 published 2018-03-07 reporter This script is Copyright (C) 2018-2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/107167 title Fedora 26 : libXfont (2018-5a7cd68500) NASL family Huawei Local Security Checks NASL id EULEROS_SA-2020-1242.NASL description According to the version of the libXfont2 package installed, the EulerOS Virtualization for ARM 64 installation on the remote host is affected by the following vulnerability : - In libXfont before 1.5.4 and libXfont2 before 2.0.3, a local attacker can open (but not read) files on the system as root, triggering tape rewinds, watchdogs, or similar mechanisms that can be triggered by opening files.(CVE-2017-16611) 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 seen 2020-03-19 modified 2020-03-13 plugin id 134531 published 2020-03-13 reporter This script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/134531 title EulerOS Virtualization for ARM 64 3.0.2.0 : libXfont2 (EulerOS-SA-2020-1242) NASL family Huawei Local Security Checks NASL id EULEROS_SA-2019-2347.NASL description According to the version of the libXfont2 package installed, the EulerOS Virtualization for ARM 64 installation on the remote host is affected by the following vulnerability : - In libXfont before 1.5.4 and libXfont2 before 2.0.3, a local attacker can open (but not read) files on the system as root, triggering tape rewinds, watchdogs, or similar mechanisms that can be triggered by opening files.(CVE-2017-16611) 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 seen 2020-06-01 modified 2020-06-02 plugin id 131512 published 2019-12-03 reporter This script is Copyright (C) 2019 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/131512 title EulerOS Virtualization for ARM 64 3.0.3.0 : libXfont2 (EulerOS-SA-2019-2347) NASL family Fedora Local Security Checks NASL id FEDORA_2018-E27B435A7F.NASL description Security fix for CVE-2017-16611 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 seen 2020-06-05 modified 2018-03-07 plugin id 107177 published 2018-03-07 reporter This script is Copyright (C) 2018-2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/107177 title Fedora 27 : libXfont (2018-e27b435a7f)
References
- http://security.cucumberlinux.com/security/details.php?id=155
- http://security.cucumberlinux.com/security/details.php?id=155
- http://www.openwall.com/lists/oss-security/2017/11/28/7
- http://www.openwall.com/lists/oss-security/2017/11/28/7
- http://www.ubuntu.com/usn/USN-3500-1
- http://www.ubuntu.com/usn/USN-3500-1
- https://bugzilla.suse.com/show_bug.cgi?id=1050459
- https://bugzilla.suse.com/show_bug.cgi?id=1050459
- https://lists.debian.org/debian-lts-announce/2022/01/msg00028.html
- https://lists.debian.org/debian-lts-announce/2022/01/msg00028.html
- https://marc.info/?l=freedesktop-xorg-announce&m=151188044218304&w=2
- https://marc.info/?l=freedesktop-xorg-announce&m=151188044218304&w=2
- https://marc.info/?l=freedesktop-xorg-announce&m=151188049718337&w=2
- https://marc.info/?l=freedesktop-xorg-announce&m=151188049718337&w=2
- https://security.gentoo.org/glsa/201801-10
- https://security.gentoo.org/glsa/201801-10