Vulnerability identifier: #VU17427

Vulnerability risk: Medium

CVSSv3.1: 5.1 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2019-1672

CWE-ID: CWE-264

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 system.

The vulnerability exists in the Decryption Policy Default Action functionality due to the incorrect handling of SSL-encrypted traffic when Decrypt for End-User Notification is disabled in the configuration. A remote attacker can send a SSL connection through the affected device to bypass a configured drop policy to block specific SSL connections and allow traffic onto the network that should have been denied.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Cisco Web Security Appliance: 10.1.0 204 - 11.5.1 FCS 115

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External links
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190206-wsa-bypass

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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.