Cisco plugs VoIP malware loophole

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Cisco rushed out a brace of security updates on Thursday to defend against potentially dangerous exploits via its VoIP kit, including the possibility of malicious code being injected into vulnerable networks.

The twin advisories from the network giant cover a range of vulnerabilities in Cisco IP Phones and its Unified Communications Manager (UCM) call management software.

A range of Cisco 7900 Series IP Phones are subject to multiple flaws, some of which may lend themselves to attacks involving the execution of arbitrary code on a vulnerable phone. Malicious DNS responses, a bug on the phone's SSH server and flaws in the handling of MIME on SIP messages all create buffer overflow risks. Other bugs create a means to crash vulnerable phones.

The bugs affect ranges of Cisco Unified IP Phone devices running both SIP firmware and SCCP firmware, as explained here. Cisco's advisory - which contains patching instructions - can be found here.

Exploitation would be tricky but updates are still recommended to guard against possible attack. Workarounds involving disabling potentially vulnerable servicse are possible but troublesome because they would stop remote management of devices, the SANS Institute Internet Storm Centre notes.

Sys admins also need to update their software to either version 5.1(3a) or 6.1(1a), as appropriate, following the discovery of a SQL injection flaw. Left unguarded the vulnerability creates a means for authenticated user to get their hands on sensitive database information, such as user names and password hashes, and call records. Logged-in users may also be able to alter or delete call records. Cisco's advisory can be found here. ®

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