Vulnerabilities > CVE-2011-0543 - Permissions, Privileges, and Access Controls vulnerability in Fuse

047910
CVSS 0.0 - NONE
Attack vector
UNKNOWN
Attack complexity
UNKNOWN
Privileges required
UNKNOWN
Confidentiality impact
UNKNOWN
Integrity impact
UNKNOWN
Availability impact
UNKNOWN

Summary

Certain legacy functionality in fusermount in fuse 2.8.5 and earlier, when util-linux does not support the --no-canonicalize option, allows local users to bypass intended access restrictions and unmount arbitrary directories via a symlink attack.

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-2011-1083.NASL
    descriptionUpdated fuse packages that fix multiple security issues are now available for Red Hat Enterprise Linux 6. The Red Hat Security Response Team has rated this update as having moderate security impact. Common Vulnerability Scoring System (CVSS) base scores, which give detailed severity ratings, are available for each vulnerability from the CVE links in the References section. FUSE (Filesystem in Userspace) can implement a fully functional file system in a user-space program. These packages provide the mount utility, fusermount, the tool used to mount FUSE file systems. Multiple flaws were found in the way fusermount handled the mounting and unmounting of directories when symbolic links were present. A local user in the fuse group could use these flaws to unmount file systems, which they would otherwise not be able to unmount and that were not mounted using FUSE, via a symbolic link attack. (CVE-2010-3879, CVE-2011-0541, CVE-2011-0542, CVE-2011-0543) Note: The util-linux-ng RHBA-2011:0699 update must also be installed to fully correct the above flaws. All users should upgrade to these updated packages, which contain backported patches to correct these issues.
    last seen2020-06-01
    modified2020-06-02
    plugin id55635
    published2011-07-21
    reporterThis script is Copyright (C) 2011-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/55635
    titleRHEL 6 : fuse (RHSA-2011:1083)
  • NASL familySuSE Local Security Checks
    NASL idSUSE_UTIL-LINUX-AND-FUSE-201103-7362.NASL
    descriptionThe following security issues were fixed in fuse and util-linux : - FUSE allowed local users to create mtab entries with arbitrary pathnames, and consequently unmount any filesystem, via a symlink attack on the parent directory of the mountpoint of a FUSE filesystem. (CVE-2010-3879) - Avoid mounting a directory including evaluation of symlinks, which might have allowed local attackers to mount filesystems anywhere in the system. (CVE-2011-0541) - Avoid symlink attacks on the mount point written in the mtab file. (CVE-2011-0543) Additional two bugs were fixed in util-linux : - fixed retrying nfs mounts on rpc timeouts - allow seperate control of the internet protocol uses by rpc.mount seperately of the protocol used by nfs. New features were implemented: - mount now has --fake and --no-canonicalize options, required for the symlink security fixes. These were backported from mainline.
    last seen2020-06-01
    modified2020-06-02
    plugin id53256
    published2011-04-01
    reporterThis script is Copyright (C) 2011-2019 Tenable Network Security, Inc.
    sourcehttps://www.tenable.com/plugins/nessus/53256
    titleSuSE 10 Security Update : FUSE (ZYPP Patch Number 7362)
  • NASL familyScientific Linux Local Security Checks
    NASL idSL_20110720_FUSE_ON_SL6_X.NASL
    descriptionFUSE (Filesystem in Userspace) can implement a fully functional file system in a user-space program. These packages provide the mount utility, fusermount, the tool used to mount FUSE file systems. Multiple flaws were found in the way fusermount handled the mounting and unmounting of directories when symbolic links were present. A local user in the fuse group could use these flaws to unmount file systems, which they would otherwise not be able to unmount and that were not mounted using FUSE, via a symbolic link attack. (CVE-2010-3879, CVE-2011-0541, CVE-2011-0542, CVE-2011-0543) All users should upgrade to these updated packages, which contain backported patches to correct these issues.
    last seen2020-06-01
    modified2020-06-02
    plugin id61086
    published2012-08-01
    reporterThis script is Copyright (C) 2012-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/61086
    titleScientific Linux Security Update : fuse on SL6.x i386/x86_64
  • NASL familyUbuntu Local Security Checks
    NASL idUBUNTU_USN-1077-1.NASL
    descriptionIt was discovered that FUSE would incorrectly follow symlinks when checking mountpoints under certain conditions. A local attacker, with access to use FUSE, could unmount arbitrary locations, leading to a denial of service. 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 seen2020-06-01
    modified2020-06-02
    plugin id52479
    published2011-03-01
    reporterUbuntu Security Notice (C) 2011-2019 Canonical, Inc. / NASL script (C) 2011-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/52479
    titleUbuntu 8.04 LTS / 9.10 / 10.04 LTS / 10.10 : fuse vulnerabilities (USN-1077-1)
  • NASL familySuSE Local Security Checks
    NASL idSUSE_11_2_FUSE-110228.NASL
    descriptionRace conditions in fuse allowed unprivileged users to umount arbitrary mount points (CVE-2011-0541,CVE-2010-3879,CVE-2011-0543).
    last seen2020-06-01
    modified2020-06-02
    plugin id53724
    published2011-05-05
    reporterThis script is Copyright (C) 2011-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/53724
    titleopenSUSE Security Update : fuse (openSUSE-SU-2011:0265-1)
  • NASL familySuSE Local Security Checks
    NASL idSUSE_11_3_FUSE-110228.NASL
    descriptionRace conditions in fuse allowed unprivileged users to umount arbitrary mount points (CVE-2011-0541,CVE-2010-3879,CVE-2011-0543).
    last seen2020-06-01
    modified2020-06-02
    plugin id75508
    published2014-06-13
    reporterThis script is Copyright (C) 2014-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/75508
    titleopenSUSE Security Update : fuse (openSUSE-SU-2011:0264-1)
  • NASL familySuSE Local Security Checks
    NASL idSUSE_11_UTIL-LINUX-AND-FUSE-201103-110302.NASL
    descriptionThe following security issues were fixed : - FUSE allowed local users to create mtab entries with arbitrary pathnames, and consequently unmount any filesystem, via a symlink attack on the parent directory of the mountpoint of a FUSE filesystem. (CVE-2010-3879) - Avoid mounting a directory including evaluation of symlinks, which might have allowed local attackers to mount filesystems anywhere in the system. (CVE-2011-0541) - Avoid symlink attacks on the mount point written in the mtab file. Four bugs were fixed:. (CVE-2011-0543) - fixed retrying nfs mounts on rpc timeouts - allow seperate control of the internet protocol uses by rpc.mount seperately of the protocol used by nfs. - Fixed locking in libuuid/uuid to avoid duplicate uuids. - mkswap bad block check marked every block bad in O(n!) time on a good device New features were implemented : - mount now has --fake and --no-canonicalize options, required for the symlink security fixes. These were backported from mainline. - mount can now auto-detect and differentiate between squashfs3 and squashfs (v4) filesystems, allowing backward compatibility to the SUSE Linux Enterprise 11 GA codebase.
    last seen2020-06-01
    modified2020-06-02
    plugin id53231
    published2011-03-31
    reporterThis script is Copyright (C) 2011-2019 Tenable Network Security, Inc.
    sourcehttps://www.tenable.com/plugins/nessus/53231
    titleSuSE 11.1 Security Update : FUSE (SAT Patch Number 4095)
  • NASL familySuSE Local Security Checks
    NASL idSUSE_UTIL-LINUX-AND-FUSE-201103-7418.NASL
    descriptionThe following security issues were fixed in fuse : - FUSE allowed local users to create mtab entries with arbitrary pathnames, and consequently unmount any filesystem, via a symlink attack on the parent directory of the mountpoint of a FUSE filesystem. (CVE-2010-3879) - Avoid mounting a directory including evaluation of symlinks, which might have allowed local attackers to mount filesystems anywhere in the system. (CVE-2011-0541) - Avoid symlink attacks on the mount point written in the mtab file. (CVE-2011-0543)
    last seen2020-06-01
    modified2020-06-02
    plugin id57257
    published2011-12-13
    reporterThis script is Copyright (C) 2011-2019 Tenable Network Security, Inc.
    sourcehttps://www.tenable.com/plugins/nessus/57257
    titleSuSE 10 Security Update : fuse (ZYPP Patch Number 7418)
  • NASL familyOracle Linux Local Security Checks
    NASL idORACLELINUX_ELSA-2011-1083.NASL
    descriptionFrom Red Hat Security Advisory 2011:1083 : Updated fuse packages that fix multiple security issues are now available for Red Hat Enterprise Linux 6. The Red Hat Security Response Team has rated this update as having moderate security impact. Common Vulnerability Scoring System (CVSS) base scores, which give detailed severity ratings, are available for each vulnerability from the CVE links in the References section. FUSE (Filesystem in Userspace) can implement a fully functional file system in a user-space program. These packages provide the mount utility, fusermount, the tool used to mount FUSE file systems. Multiple flaws were found in the way fusermount handled the mounting and unmounting of directories when symbolic links were present. A local user in the fuse group could use these flaws to unmount file systems, which they would otherwise not be able to unmount and that were not mounted using FUSE, via a symbolic link attack. (CVE-2010-3879, CVE-2011-0541, CVE-2011-0542, CVE-2011-0543) Note: The util-linux-ng RHBA-2011:0699 update must also be installed to fully correct the above flaws. All users should upgrade to these updated packages, which contain backported patches to correct these issues.
    last seen2020-06-01
    modified2020-06-02
    plugin id68309
    published2013-07-12
    reporterThis script is Copyright (C) 2013-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/68309
    titleOracle Linux 6 : fuse (ELSA-2011-1083)

Redhat

advisories
bugzilla
id651183
titleCVE-2010-3879 CVE-2011-0541 CVE-2011-0542 CVE-2011-0543 fuse: unprivileged user can unmount arbitrary locations via symlink attack
oval
OR
  • commentRed Hat Enterprise Linux must be installed
    ovaloval:com.redhat.rhba:tst:20070304026
  • AND
    • commentRed Hat Enterprise Linux 6 is installed
      ovaloval:com.redhat.rhba:tst:20111656003
    • OR
      • AND
        • commentfuse-devel is earlier than 0:2.8.3-3.el6_1
          ovaloval:com.redhat.rhsa:tst:20111083001
        • commentfuse-devel is signed with Red Hat redhatrelease2 key
          ovaloval:com.redhat.rhsa:tst:20111083002
      • AND
        • commentfuse is earlier than 0:2.8.3-3.el6_1
          ovaloval:com.redhat.rhsa:tst:20111083003
        • commentfuse is signed with Red Hat redhatrelease2 key
          ovaloval:com.redhat.rhsa:tst:20111083004
      • AND
        • commentfuse-libs is earlier than 0:2.8.3-3.el6_1
          ovaloval:com.redhat.rhsa:tst:20111083005
        • commentfuse-libs is signed with Red Hat redhatrelease2 key
          ovaloval:com.redhat.rhsa:tst:20111083006
rhsa
idRHSA-2011:1083
released2011-07-20
severityModerate
titleRHSA-2011:1083: fuse security update (Moderate)
rpms
  • fuse-0:2.8.3-3.el6_1
  • fuse-debuginfo-0:2.8.3-3.el6_1
  • fuse-devel-0:2.8.3-3.el6_1
  • fuse-libs-0:2.8.3-3.el6_1