ID CVE-2018-1063
Summary Context relabeling of filesystems is vulnerable to symbolic link attack, allowing a local, unprivileged malicious entity to change the SELinux context of an arbitrary file to a context with few restrictions. This only happens when the relabeling process is done, usually when taking SELinux state from disabled to enable (permissive or enforcing). The issue was found in policycoreutils 2.5-11.
References
Vulnerable Configurations
  • cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*
    cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*
  • cpe:2.3:a:selinux_project:selinux:-:*:*:*:*:*:*:*
    cpe:2.3:a:selinux_project:selinux:-:*:*:*:*:*:*:*
CVSS
Base: 3.3 (as of 12-04-2018 - 01:29)
Impact:
Exploitability:
CWE CWE-59
CAPEC
  • Manipulating Web 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.
  • 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.
  • Using Malicious 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.
  • 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.
Access
VectorComplexityAuthentication
LOCAL MEDIUM NONE
Impact
ConfidentialityIntegrityAvailability
PARTIAL PARTIAL NONE
cvss-vector via4 AV:L/AC:M/Au:N/C:P/I:P/A:N
redhat via4
advisories
bugzilla
id 1550122
title CVE-2018-1063 policycoreutils: Relabelling of symbolic links in /tmp and /var/tmp change the context of their target instead
oval
OR
  • comment Red Hat Enterprise Linux must be installed
    oval oval:com.redhat.rhba:tst:20070304026
  • AND
    • comment Red Hat Enterprise Linux 7 is installed
      oval oval:com.redhat.rhba:tst:20150364027
    • OR
      • AND
        • comment policycoreutils is earlier than 0:2.5-22.el7
          oval oval:com.redhat.rhsa:tst:20180913001
        • comment policycoreutils is signed with Red Hat redhatrelease2 key
          oval oval:com.redhat.rhsa:tst:20110414012
      • AND
        • comment policycoreutils-devel is earlier than 0:2.5-22.el7
          oval oval:com.redhat.rhsa:tst:20180913003
        • comment policycoreutils-devel is signed with Red Hat redhatrelease2 key
          oval oval:com.redhat.rhsa:tst:20162702014
      • AND
        • comment policycoreutils-gui is earlier than 0:2.5-22.el7
          oval oval:com.redhat.rhsa:tst:20180913005
        • comment policycoreutils-gui is signed with Red Hat redhatrelease2 key
          oval oval:com.redhat.rhsa:tst:20110414014
      • AND
        • comment policycoreutils-newrole is earlier than 0:2.5-22.el7
          oval oval:com.redhat.rhsa:tst:20180913007
        • comment policycoreutils-newrole is signed with Red Hat redhatrelease2 key
          oval oval:com.redhat.rhsa:tst:20110414016
      • AND
        • comment policycoreutils-python is earlier than 0:2.5-22.el7
          oval oval:com.redhat.rhsa:tst:20180913009
        • comment policycoreutils-python is signed with Red Hat redhatrelease2 key
          oval oval:com.redhat.rhsa:tst:20110414018
      • AND
        • comment policycoreutils-restorecond is earlier than 0:2.5-22.el7
          oval oval:com.redhat.rhsa:tst:20180913011
        • comment policycoreutils-restorecond is signed with Red Hat redhatrelease2 key
          oval oval:com.redhat.rhsa:tst:20162702019
      • AND
        • comment policycoreutils-sandbox is earlier than 0:2.5-22.el7
          oval oval:com.redhat.rhsa:tst:20180913013
        • comment policycoreutils-sandbox is signed with Red Hat redhatrelease2 key
          oval oval:com.redhat.rhsa:tst:20110414020
rhsa
id RHSA-2018:0913
released 2018-04-10
severity Low
title RHSA-2018:0913: policycoreutils security, bug fix, and enhancement update (Low)
rpms
  • policycoreutils-0:2.5-22.el7
  • policycoreutils-debuginfo-0:2.5-22.el7
  • policycoreutils-devel-0:2.5-22.el7
  • policycoreutils-gui-0:2.5-22.el7
  • policycoreutils-newrole-0:2.5-22.el7
  • policycoreutils-python-0:2.5-22.el7
  • policycoreutils-restorecond-0:2.5-22.el7
  • policycoreutils-sandbox-0:2.5-22.el7
refmap via4
confirm https://bugzilla.redhat.com/show_bug.cgi?id=1550122
Last major update 12-04-2018 - 01:29
Published 02-03-2018 - 15:29
Last modified 12-04-2018 - 01:29
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