Debian update for libssh

1) Buffer overflow

EUVDB-ID: #VU56217

Risk: High

CVSSv3.1: 7.1 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-3634

CWE-ID: CWE-119 - Memory corruption

Exploit availability: No

Description

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

The vulnerability exists due to a boundary error when handling shared secrets. A remote attacker can supply a shared secret of a different size, trigger a memory corruption during the second key re-exchange and crash the application or potentially execute arbitrary code.

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

Mitigation

Update libssh package to version 0.9.5-1+deb11u1.

Vulnerable software versions

libssh (Debian package): 0.9.0-1 - 0.9.5-1

External links

http://www.debian.org/security/2021/dsa-4965

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.