Red Hat Enterprise Linux 9 update for openssh

1) Double Free

EUVDB-ID: #VU71771

Risk: High

CVSSv3.1: 7.3 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C]

CVE-ID: CVE-2023-25136

CWE-ID: CWE-415 - Double Free

Exploit availability: Yes

Description

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

The vulnerability exists due to a boundary error within the sshd(8) daemon. A remote non-authenticated attacker can send  specially crafted data to the application, trigger a double free error and execute arbitrary code on the target system.

The vendor believes exploitation of this vulnerability has limitations as double free occurs "in the unprivileged pre-auth process that is subject to chroot(2) and is further sandboxed on most major platforms". Nevertheless we assign a high risk to this vulnerability.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Red Hat Enterprise Linux for ARM 64: 9

Red Hat Enterprise Linux for Power, little endian: 9

Red Hat Enterprise Linux for IBM z Systems: 9

Red Hat Enterprise Linux for x86_64: 9

openssh (Red Hat package): before 8.7p1-29.el9_2

External links

http://access.redhat.com/errata/RHSA-2023:2645

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.