Keepalived Symlink Pathnames Arbitrary File Overwrite Vulnerability [CVE-2018-19044 ]

CVE Number – CVE-2018-19044

A vulnerability in Keepalived could allow a local attacker to overwrite arbitrary files on a targeted system.

The vulnerability is due to improper permissions checks for pathnames with symbolic links (symlinks) when a PrintData or PrintStats call is invoked and fs.protected_symlinks is set to 0. An attacker could exploit this vulnerability by accessing an affected system and creating a new temporary file to be used as a symbolic link, then making a PrintData or PrintStats call that submits malicious input to the system. A successful exploit could allow the attacker to access sensitive information or cause a denial of service (DoS) condition by overwriting arbitrary files, such as the /etc/passwd file. 

Proof-of-concept (PoC) code that demonstrates an exploit of this vulnerability is publicly available. 

Keepalived.org has confirmed the vulnerability and released software updates.

Analysis

  • To exploit this vulnerability, the attacker must have user-level access to the targeted system. This access requirement may reduce the likelihood of a successful exploit.

Safeguards

  • Administrators are advised to apply the appropriate updates.

    Administrators are advised to allow only trusted users to access local systems.

    Administrators are advised to allow only privileged users to access administration or management systems.

    Administrators are advised to monitor critical systems.

Vendor Announcements

Fixed Software

  • Keepalived.org has released software updates at the following link: keepalived 2.0.9

Duncan Newell

Duncan is a technology professional with over 20 years experience of working in various IT roles. He has a interest in cyber security, and has a wide range of other skills in radio, electronics and telecommunications.

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