#VU28390 Symlink attack in Linux kernel - CVE-2000-1134

Vulnerability identifier: #VU28390

Vulnerability risk: Low

CVSSv4.0: 5.9 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2000-1134

CWE-ID: CWE-61

Exploitation vector: Local

Exploit availability: No

Vulnerable software:
Linux kernel
Operating systems & Components / Operating system

Vendor: Linux Foundation

Description

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

Multiple shell programs on various Unix systems, including (1) tcsh, (2) csh, (3) sh, and (4) bash, follow symlinks when processing << redirects (aka here-documents or in-here documents), which allows local users to overwrite files of other users via a symlink attack.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Linux kernel: 4.4 - 4.4.165, 4.9 - 4.9.141, 4.14 - 4.14.84

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External links
https://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.14.85
https://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.4.166
https://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.9.142

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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.