#VU13232 Security restrictions bypass in Cisco Web Security Appliance - CVE-2018-0353

Vulnerability identifier: #VU13232

Vulnerability risk: Low

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

CVE-ID: CVE-2018-0353

CWE-ID: CWE-20

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Cisco Web Security Appliance
Server applications / IDS/IPS systems, Firewalls and proxy servers

Vendor: Cisco Systems, Inc

Description

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

The vulnerability exists in traffic-monitoring functions in Cisco Web Security Appliance (WSA) due to a change in the underlying operating system software that is responsible for monitoring affected traffic. A remote unauthenticated attacker can send a specially crafted IP packets, circumvent Layer 4 Traffic Monitor (L4TM) functionality, pass traffic through the device, which the WSA was configured to deny.

Mitigation
The vulnerability is addressed in the following versions: 11.5.0-614, 10.5.2-061.

Vulnerable software versions

Cisco Web Security Appliance: 10.5.1 - 11.0.0

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External links
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180606-wsa

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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.