#VU64412 Path traversal in Loki - CVE-2021-36156

Vulnerability identifier: #VU64412

Vulnerability risk: Medium

CVSSv4.0: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2021-36156

CWE-ID: CWE-22

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Loki
Web applications / Other software

Vendor: Grafana Labs

Description

The vulnerability allows a remote attacker to perform directory traversal attacks.

The vulnerability exists due to input validation error when header value X-Scope-OrgID is used to construct file paths for rules files. A remote attacker can send a specially crafted HTTP request and read arbitrary files on the system.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Loki: 0.1.0, 0.2.0, 0.3.0, 0.4.0, 1.0.0 - 1.0.2, 1.1.0, 1.2.0, 1.3.0, 1.4.0 - 1.4.1, 1.5.0, 1.6.0 - 1.6.1, 2.0.0 - 2.0.1, 2.1.0, 2.2.0

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External links
https://github.com/grafana/loki/pull/4020#issue-694377133
https://github.com/grafana/loki/releases/tag/v2.3.0

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

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