#VU16928 Security restrictions bypass in Cisco IOS - CVE-2018-0484

Vulnerability identifier: #VU16928

Vulnerability risk: Low

CVSSv4.0: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2018-0484

CWE-ID: CWE-119

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Cisco IOS
Operating systems & Components / Operating system

Vendor: Cisco Systems, Inc

Description

The vulnerability allows a remote attacker to bypass security restrictions on the target system.

The vulnerability exists in the access control logic of the Secure Shell (SSH) server due to a missing check in the SSH server. A remote unauthenticated attacker can open an SSH connection to an affected Cisco IOS or IOS XE device with a source address belonging to a VRF instance and forward the instance despite the absence of the vrf-also keyword in the access-class configuration.

Mitigation
The vulnerability has been fixed in the versions 16.6.5, 16.6(4.12), 15.8(3.1s)M, 15.8(3)M1.

Vulnerable software versions

Cisco IOS: 16.6.2 - 16.6.4

---

External links
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190109-ios-ssh-vrf

---

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.