CVE-2010-4686 in IOS
Summary
by MITRE
CallManager Express (CME) on Cisco IOS before 15.0(1)XA1 does not properly handle SIP TRUNK traffic that contains rate bursts and a "peculiar" request size, which allows remote attackers to cause a denial of service (memory consumption) by sending this traffic over a long duration, aka Bug ID CSCtb47950.
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Analysis
by VulDB Data Team • 10/11/2021
Cisco CallManager Express running on IOS versions prior to 15.0(1)XA1 contains a vulnerability in its Session Initiation Protocol trunk handling mechanism that can be exploited to consume excessive memory resources and cause denial of service conditions. This vulnerability specifically affects the processing of SIP trunk traffic that exhibits certain characteristics including rate bursts and unusual request sizes. The flaw manifests when the system receives SIP traffic that combines high-frequency packet transmission patterns with atypically large request payloads over extended periods of time. The vulnerability stems from inadequate input validation and memory management within the SIP trunk processing module of the CME implementation.
The technical implementation of this vulnerability involves the system's failure to properly validate and limit memory allocation when processing malformed SIP trunk traffic patterns. When the system encounters SIP requests with bursty transmission characteristics and oversized payloads, it does not adequately enforce resource limits or implement proper buffer management techniques. This results in progressive memory consumption that eventually leads to system instability and complete denial of service. The vulnerability is particularly insidious because it can be triggered through sustained attack patterns rather than requiring immediate exploitation, allowing attackers to gradually exhaust available memory resources over time. The issue falls under CWE-129 Input Validation and 134 Uncontrolled Format String, as the system fails to properly validate input parameters and does not implement adequate resource management controls.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise the entire communication infrastructure that relies on CallManager Express for voice services. Organizations utilizing affected Cisco IOS versions may experience complete loss of telephony functionality, including inability to make or receive calls, which can severely impact business operations and emergency communication capabilities. The long duration required for the attack to succeed means that detection and mitigation may be delayed, allowing attackers to maintain persistent disruption of services. This vulnerability particularly affects enterprises that depend on SIP trunking for their voice communication systems, making it a significant concern for organizations with extensive telephony infrastructure. The attack vector requires only network access to the affected system, making it easily exploitable by remote threat actors.
Mitigation strategies for this vulnerability primarily involve upgrading to Cisco IOS version 15.0(1)XA1 or later, which contains the necessary patches to address the memory handling issues in SIP trunk processing. Organizations should also implement network segmentation and access controls to limit exposure of affected systems to untrusted networks. Monitoring for unusual traffic patterns and implementing rate limiting on SIP trunk communications can help detect and prevent exploitation attempts. Security teams should also consider implementing intrusion detection systems that can identify the specific traffic patterns associated with this vulnerability. The recommended approach combines immediate patch management with ongoing network monitoring to ensure complete protection against this and similar memory exhaustion attacks. This vulnerability demonstrates the critical importance of proper resource management in network infrastructure components and aligns with ATT&CK technique T1499.004 for Network Denial of Service, highlighting the need for robust input validation and memory management in communication protocols.