Remote code execution in SSH server in Fortinet FortiOS

1) Format string error

EUVDB-ID: #VU17231

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-2018-1352

CWE-ID: CWE-134 - Use of Externally-Controlled Format String

Exploit availability: No

Description

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

The vulnerability exists due to a format string error when processing supplied username within the SSH server. A remote attacker can supply a specially crafted username that contains format string specifiers, trigger memory corruption 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

FortiOS: 5.6.0

External links

http://fortiguard.com/psirt/FG-IR-18-018

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.