Remote denial of service in Cisco Expressway and TelePresence VCS

1) Memory corruption

EUVDB-ID: #VU12994

Risk: Medium

CVSSv4.0: 6.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2017-3790

CWE-ID: CWE-119 - Memory corruption

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to boundary error when processing h323 calls. A remote unauthenticated attacker can initiate connection to the vulnerable service, send specially crafted h224 data in Real-Time Transport Protocol (RTP) packets, trigger memory corruption and h323 call parser and crash the service.

Successful exploitation of the vulnerability requires that the attacker can send network packets to h323 interface.

Mitigation

Update to version X8.8.2.

Vulnerable software versions

Cisco Expressway: X8.1 - X8.8.1

Cisco TelePresence Video Communication Server: All versions

CPE2.3

• cpe:2.3:a:cisco_systems:cisco_expressway:X8.1:*:*:*:*:*:*:*
• cpe:2.3:a:cisco_systems:cisco_expressway:X8.1.1:*:*:*:*:*:*:*
• cpe:2.3:a:cisco_systems:cisco_expressway:X8.1.2:*:*:*:*:*:*:*
• cpe:2.3:a:cisco_systems:cisco_telepresence_video_communication_server:*:*:*:*:*:*:*:*

External links

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170125-expressway
https://bst.cloudapps.cisco.com/bugsearch/bug/CSCus99263

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.