CVE-2014-3361 in IOS
Summary
by MITRE
The ALG module in Cisco IOS 15.0 through 15.4 does not properly implement SIP over NAT, which allows remote attackers to cause a denial of service (device reload) via multipart SDP IPv4 traffic, aka Bug ID CSCun54071.
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Analysis
by VulDB Data Team • 12/17/2024
The vulnerability identified as CVE-2014-3361 represents a critical flaw in Cisco IOS operating systems affecting versions 15.0 through 15.4. This issue resides within the Application Layer Gateway (ALG) module specifically related to Session Initiation Protocol (SIP) handling over Network Address Translation environments. The flaw manifests when the system processes multipart SDP IPv4 traffic that contains certain malformed or unexpected packet sequences, leading to a complete device reload and subsequent denial of service condition.
The technical implementation of this vulnerability stems from insufficient validation and handling of SIP protocol elements within the NAT traversal mechanisms of the ALG module. When the system encounters multipart SDP messages containing specific patterns of IPv4 addresses and port information, the internal state management fails to properly process these packets, causing memory corruption and ultimately resulting in an unhandled exception that triggers a device restart. This behavior aligns with CWE-129, which describes issues related to improper validation of input boundaries, and specifically relates to improper handling of protocol state transitions in network security appliances.
The operational impact of this vulnerability extends beyond simple service disruption as it provides attackers with a reliable method to perform denial of service attacks against Cisco IOS devices without requiring authentication or privileged access. Attackers can exploit this vulnerability by sending specifically crafted multipart SDP IPv4 packets to devices running affected IOS versions, causing them to repeatedly reload and making the network infrastructure unavailable to legitimate users. The vulnerability affects network infrastructure devices that utilize SIP ALG functionality, including routers and switches that support VoIP services and multimedia communications, potentially impacting enterprise networks, service providers, and critical communication infrastructures.
Organizations should implement immediate mitigations including disabling the SIP ALG functionality on affected devices when SIP services are not required, applying the latest Cisco IOS patches that address the specific buffer handling issues in the ALG module, and implementing network segmentation to limit exposure of vulnerable devices. Network administrators should also consider deploying intrusion detection systems that can identify and block malicious SDP traffic patterns, and establish monitoring procedures to detect device reload events that may indicate exploitation attempts. The vulnerability demonstrates the importance of proper protocol implementation in network security devices and aligns with ATT&CK technique T1499.004, which covers network denial of service attacks through exploitation of protocol implementation flaws in network infrastructure devices.