Vulnerability identifier: #VU62084

Vulnerability risk: High

CVSSv3.1: 8.8 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C]

CVE-ID: CVE-2021-31805

CWE-ID: CWE-94

Exploitation vector: Network

Exploit availability: Yes

Vulnerable software:
Apache Struts
Server applications / Frameworks for developing and running applications

Vendor: Apache Foundation

Description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to improper input validation caused by incomplete fix for #VU48815 (CVE-220-17530). Still some of the tag's attributes could perform a double evaluation if a developer applied forced OGNL evaluation by using the %{...} syntax. A remote attacker can send a specially crafted request and execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Apache Struts: 2.0.0 - 2.5.29

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External links
http://cwiki.apache.org/confluence/display/WW/S2-062

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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. However, proof of concept for this vulnerability is available.