CVE-2014-2106 in IOS
Summary
by MITRE
Cisco IOS 15.3M before 15.3(3)M2 and IOS XE 3.10.xS before 3.10.2S allow remote attackers to cause a denial of service (device reload) via crafted SIP messages, aka Bug ID CSCug45898.
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Analysis
by VulDB Data Team • 05/09/2026
Cisco IOS version 15.3M prior to 15.3(3)M2 and IOS XE version 3.10.xS prior to 3.10.2S contain a vulnerability that permits remote attackers to trigger a denial of service condition resulting in device reload through the exploitation of crafted Session Initiation Protocol SIP messages. This vulnerability represents a critical flaw in the SIP processing mechanism within the affected Cisco IOS and IOS XE software versions, where the system fails to properly validate incoming SIP traffic, leading to unexpected system behavior and subsequent device restarts. The flaw specifically impacts the signaling processing capabilities of the network infrastructure devices, affecting routers and switches that handle SIP communications for VoIP services. The vulnerability is classified under CWE-129, which addresses insufficient input validation, and aligns with ATT&CK technique T1499.004 for network denial of service attacks. The attack vector requires remote access to the network device through SIP protocol endpoints, making it particularly dangerous as it can be exploited from outside the network perimeter without requiring physical access or authentication credentials.
The technical implementation of this vulnerability stems from inadequate bounds checking and input validation within the SIP message parser component of the affected software versions. When the device receives a malformed or specially crafted SIP message, the parsing routine fails to properly handle the unexpected data structure, causing the system to enter an unstable state that ultimately results in a complete device reload. This behavior demonstrates a classic buffer over-read or memory corruption issue where the application does not adequately sanitize the incoming SIP message content before processing. The impact extends beyond simple service disruption as the device reload process can interrupt ongoing network communications, potentially affecting voice services, data transmission, and network availability for legitimate users. The vulnerability affects devices running Cisco IOS and IOS XE software that support SIP signaling protocols, which are commonly deployed in enterprise networks, service provider environments, and telecommunications infrastructure where VoIP services are implemented.
The operational impact of this vulnerability is significant for organizations relying on Cisco network infrastructure for voice communications and signaling services. Network administrators may experience unexpected device downtime, service interruptions for VoIP users, and potential cascading effects throughout the network infrastructure if multiple devices are affected. The remote exploitability means that attackers can target these devices from anywhere on the internet, making the vulnerability particularly dangerous for public-facing network equipment. Organizations may also face compliance and regulatory challenges if their network infrastructure is found to be vulnerable to such attacks, especially in industries with strict availability requirements. The vulnerability can be exploited by malicious actors to perform sustained denial of service attacks against critical network infrastructure, potentially leading to financial losses, service degradation, and operational disruptions. Security teams must consider the potential for this vulnerability to be used as part of larger attack campaigns targeting network availability, particularly when combined with other exploitation techniques.
Organizations should implement immediate mitigation strategies including applying the relevant security patches and updates provided by Cisco to address this vulnerability in affected software versions. The recommended solution involves upgrading to Cisco IOS 15.3(3)M2 or later for IOS 15.3M versions, and IOS XE 3.10.2S or later for IOS XE 3.10.xS versions. Network administrators should also consider implementing network segmentation and access controls to limit exposure of SIP-enabled devices to untrusted networks. Additional protective measures include configuring SIP message filtering and rate limiting on network devices to prevent malicious traffic from reaching the vulnerable components. The implementation of intrusion detection systems and monitoring solutions can help detect exploitation attempts and provide early warning of potential attacks. Organizations should also conduct thorough vulnerability assessments to identify all devices running affected software versions and prioritize patching activities based on risk assessment. Regular security audits and network monitoring should be maintained to ensure continued protection against similar vulnerabilities and to verify that mitigation measures remain effective against evolving threat landscapes.