UNIX symbolic link following in keepalived (Alpine package)

1) UNIX symbolic link following

EUVDB-ID: #VU15789

Risk: Low

CVSSv4.0: 0.4 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2018-19044

CWE-ID: CWE-61 - UNIX Symbolic Link (Symlink) Following

Exploit availability: No

Description

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to a symlink following issue when writing data to a temporary file upon a call to PrintData or PrintStats. A local user can create a specially crafted symbolic link to a critical file on the system and overwrite it with privileges of the application, if fs.protected_symlinks is set to 0.

Successful exploitation of this vulnerability may result in privilege escalation.

Mitigation

Install update from vendor's website.

Vulnerable software versions

keepalived (Alpine package): 2.0.5-r0 - 2.0.7-r1

CPE2.3

• cpe:2.3:a:alpine:keepalived_alpine_package:2.0.5-r0:*:*:*:*:alpine_linux:*:3.7
• cpe:2.3:a:alpine:keepalived_alpine_package:2.0.7-r1:*:*:*:*:alpine_linux:*:3.8

External links

https://git.alpinelinux.org/aports/commit/?id=b0db67a5a9a6e1d6299a426bcbbb56da356da370
https://git.alpinelinux.org/aports/commit/?id=d5456c04c54ef1071228fe009595f420a2dd7e42

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.