Vulnerability identifier: #VU57553

Vulnerability risk: High

CVSSv3.1: 8.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-41991

CWE-ID: CWE-190

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
strongSwan
Server applications / Encryption software

Vendor: strongswan.org

Description

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

The vulnerability exists due to integer overflow when processing multiple requests with different certificates. A remote attacker can send specially crafted data to the application, trigger integer overflow 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

strongSwan: 5.0.0 - 5.9.3

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External links
http://www.strongswan.org/blog/2021/10/18/strongswan-vulnerability-(cve-2021-41991).html
http://github.com/strongswan/strongswan/releases/tag/5.9.4

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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.