Security Experts:

Vulnerability Has Been Lurking in Avaya Phones for 10 Years

A security vulnerability discovered and patched 10 years ago has remained unaddressed in various Avaya phones until recently, McAfee security researchers have discovered. 

The flaw is a stack-based buffer overflow flaw that exists in the Dynamic Host Configuration Protocol (DHCP) client. Tracked as CVE-2009-0692, the issue could be exploited using malicious DHCP response to crash the ISC DHCP client and execute arbitrary code with the permissions of the client.

The DHCP protocol was designed to allow individual devices on an IP network to get their own network configuration information, such as IP address, subnet mask, and broadcast address.

Avaya, one of the largest Voice-over-IP (VoIP) solutions providers out there, failed to address the issue in some of its devices after it apparently copied and modified a piece of open-source software. 

Although the bug affecting the software was reported in 2009, the VoIP provider failed to apply subsequent security patches, thus rendering devices and their users vulnerable. 

The existence of this vulnerability in the company’s products remained unnoticed until recently. However, it appears that only the H.323 software stack is affected (the SIP stack that can also be used with these phones is not vulnerable).

A second issue discovered in the Avaya phones was discovered 8 years ago, in 2011. Tracked as CVE-2011-0997, the bug is due to the DHCP client daemon, dhclient, not sufficiently sanitizing certain options provided in DHCP server replies, such as the client hostname. Thus, a malicious DHCP server could send these options with a specially-crafted value to a DHCP client. 

“If this option's value was saved on the client system, and then later insecurely evaluated by a process that assumes the option is trusted, it could lead to arbitrary code execution with the privileges of that process,” Avaya explains in an advisory.

These vulnerabilities impact 9600 Series IP Deskphones, J100 Series IP Phones, and B100 Series Conference Phones (B189) that run the H.323 software stack.

Avaya released software patches for these vulnerabilities on June 25. 

McAfee, which discovered the issues and reported them to Avaya, has published a video to demonstrate how an attacker could abuse these flaws to access data on the target devices.

“IoT and embedded devices tend to blend into our environment, in some cases not warranting a second thought about the security and privacy risks they pose. In this case, with a minimal hardware investment and free software, we were able to uncover a critical bug that remained out-of-sight for more than a decade,” McAfee concluded. 

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