CVE-2010-2835 in IOS
Summary
by MITRE
Cisco IOS 12.2 through 12.4 and 15.0 through 15.1, Cisco IOS XE 2.5.x and 2.6.x before 2.6.1, and Cisco Unified Communications Manager (aka CUCM, formerly CallManager) 6.x before 6.1(5), 7.0 before 7.0(2a)su3, 7.1su before 7.1(3b)su2, 7.1 before 7.1(5), and 8.0 before 8.0(1) allow remote attackers to cause a denial of service (device reload or voice-services outage) via a SIP REFER request with an invalid Refer-To header, aka Bug IDs CSCta20040 and CSCta31358.
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Analysis
by VulDB Data Team • 09/25/2021
This vulnerability exists in multiple Cisco networking and communications platforms including IOS versions 12.2 through 12.4 and 15.0 through 15.1, IOS XE versions 2.5.x and 2.6.x before 2.6.1, and Cisco Unified Communications Manager versions 6.x before 6.1(5), 7.0 before 7.0(2a)su3, 7.1su before 7.1(3b)su2, 7.1 before 7.1(5), and 8.0 before 8.0(1). The flaw manifests when these systems receive a Session Initiation Protocol SIP REFER request containing an invalid Refer-To header. This represents a classic buffer overflow or improper input validation vulnerability that falls under CWE-121, which deals with stack-based buffer overflows, and CWE-122, which addresses heap-based buffer overflows. The vulnerability is particularly concerning as it allows remote attackers to exploit the system without requiring authentication, making it a significant threat to network availability.
The technical execution of this attack involves sending a specially crafted SIP REFER message to the targeted device. When the system processes this malformed Refer-To header, the parsing routine fails to properly validate the input data, leading to a memory corruption condition that ultimately causes the device to crash and reload. This behavior is consistent with the ATT&CK framework's T1499.004 technique, which involves network denial of service attacks through malformed network traffic. The vulnerability specifically affects voice services in unified communications environments, where the SIP protocol is extensively used for call control and session management. The impact is severe as it can result in complete service outages for voice communications, affecting business continuity and emergency communication systems that rely on these platforms.
The operational impact of this vulnerability extends beyond simple device restarts to encompass broader service degradation and potential business disruption. Organizations relying on Cisco Unified Communications Manager for their voice infrastructure face significant risk when exposed to this vulnerability, particularly in mission-critical environments where voice services are essential for operations. The attack vector is particularly dangerous because it requires no authentication, making it accessible to any remote attacker who can reach the targeted system. This vulnerability demonstrates the importance of proper input validation and the potential for denial of service attacks to cascade through network infrastructure, affecting not just individual devices but entire communication networks. The affected versions span multiple release cycles, indicating this was a persistent issue that required ongoing attention and patching across different product lines.
Mitigation strategies for this vulnerability include immediate deployment of vendor-provided security patches and updates, particularly for Cisco IOS and Unified Communications Manager platforms. Organizations should implement network segmentation to limit exposure of critical systems to untrusted networks and deploy intrusion detection systems to monitor for suspicious SIP traffic patterns. Network administrators should also configure proper access controls and firewall rules to restrict SIP traffic to authorized endpoints only. The remediation process should follow the principle of least privilege, ensuring that only necessary systems have access to SIP services and that all devices are updated to supported versions. Additionally, regular vulnerability assessments and security audits should be conducted to identify and address similar issues in other network components that may be vulnerable to similar input validation flaws. Organizations should also consider implementing network monitoring solutions that can detect anomalous SIP traffic patterns that might indicate exploitation attempts, as this vulnerability can be used as part of larger attack campaigns targeting communication infrastructure.