CVE-2008-0530 in Skinny Client Control Protocol
Summary
by MITRE
Buffer overflow in Cisco Unified IP Phone 7940, 7940G, 7960, and 7960G running SCCP and SIP firmware might allow remote attackers to execute arbitrary code via a crafted DNS response.
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Analysis
by VulDB Data Team • 08/05/2019
The vulnerability identified as CVE-2008-0530 represents a critical buffer overflow flaw affecting Cisco Unified IP Phone models 7940, 7940G, 7960, and 7960G when operating with either SCCP or SIP firmware protocols. This security weakness resides in the phones' handling of DNS responses, creating an avenue for remote code execution attacks that could compromise the entire device and potentially provide attackers with unauthorized access to the underlying network infrastructure. The vulnerability is particularly concerning given the widespread deployment of these IP phone models in enterprise environments where they serve as critical communication endpoints.
The technical implementation of this flaw occurs within the phone's DNS resolution process where insufficient input validation allows attackers to craft malicious DNS responses that exceed the allocated buffer space. When the affected phones process these crafted responses, the overflow conditions trigger memory corruption that can be exploited to overwrite critical program execution pointers or inject malicious code into the phone's operating system. This buffer overflow vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and represents a classic example of how improper input handling can lead to arbitrary code execution in networked devices.
The operational impact of this vulnerability extends beyond individual device compromise to potentially affect entire network communication infrastructures. Attackers exploiting this weakness could gain complete control over affected IP phones, enabling them to intercept voice communications, manipulate call routing, or use the devices as entry points for further network penetration. The remote nature of the attack means that adversaries need not have physical access to the devices, making this vulnerability particularly dangerous in environments where network security controls may be insufficient. This type of attack vector corresponds to ATT&CK technique T1210, which covers exploitation of remote services through network-based attacks.
Mitigation strategies for CVE-2008-0530 should prioritize immediate firmware updates from Cisco, as the company released patches addressing this specific buffer overflow condition. Network administrators should also implement DNS sinkholing or filtering mechanisms to prevent malicious DNS responses from reaching affected devices, while deploying network segmentation to limit the potential impact of successful exploitation. Additional protective measures include disabling unnecessary network services on the phones, implementing network access control lists, and monitoring for unusual DNS query patterns that might indicate exploitation attempts. The vulnerability demonstrates the critical importance of maintaining up-to-date firmware in networked communication devices and highlights how seemingly minor implementation flaws in network protocols can lead to significant security breaches in enterprise environments.