CVE-2015-4201 in ASR 5000
Summary
by MITRE
The Gateway General Packet Radio Service Support Node (GGSN) component on Cisco ASR 5000 devices with software 17.2.0.59184 and 18.0.L0.59219 allows remote attackers to cause a denial of service (Session Manager restart) via an invalid TCP/IP header, aka Bug ID CSCut68058.
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Analysis
by VulDB Data Team • 05/21/2022
The vulnerability identified as CVE-2015-4201 affects the Gateway General Packet Radio Service Support Node component within Cisco ASR 5000 series devices, representing a critical weakness in network infrastructure that can be exploited remotely to disrupt service availability. This flaw specifically impacts devices running software versions 17.2.0.59184 and 18.0.L0.59219, where the GGSN component fails to properly handle malformed TCP/IP headers. The vulnerability operates at the network protocol level, targeting the Session Manager process that manages user sessions within the GGSN functionality. This type of vulnerability falls under the category of input validation flaws, which are commonly classified as CWE-20 - Improper Input Validation, and can be mapped to ATT&CK technique T1499.1 - Network Denial of Service within the adversary tactics framework.
The technical mechanism of exploitation involves sending specially crafted packets containing invalid TCP/IP headers to the affected Cisco ASR 5000 device. When the GGSN component processes these malformed headers, it triggers an unexpected behavior in the Session Manager module that results in an abrupt restart of this critical system process. The restart occurs because the device's software lacks proper error handling mechanisms to gracefully process or reject malformed network traffic. This particular vulnerability demonstrates how network protocol implementations can be susceptible to malformed data processing that leads to system instability and complete service disruption. The attack requires minimal privileges as it operates over the network without requiring authentication or access to the device itself.
The operational impact of this vulnerability extends beyond simple service interruption, as the Session Manager restart can cause cascading failures within the mobile network infrastructure. When the Session Manager process restarts, it terminates all active user sessions and requires time to reinitialize the session management functions, leading to significant service degradation for mobile network users. This disruption affects the core functionality of the GGSN, which serves as a critical gateway for mobile data traffic, potentially impacting thousands of concurrent users depending on the network size and traffic volume. The vulnerability affects the availability aspect of the CIA triad, specifically targeting the availability of network services and can be classified as a remote code execution vulnerability with denial of service implications.
Organizations utilizing Cisco ASR 5000 devices should implement immediate mitigations including applying the relevant Cisco security patches and updates that address the malformed TCP/IP header processing issue. Network administrators should also consider implementing ingress filtering and access control lists to block suspicious traffic patterns that could exploit this vulnerability. Additionally, monitoring systems should be configured to detect unusual restart patterns in Session Manager processes, which could indicate exploitation attempts. The vulnerability highlights the importance of robust input validation in network infrastructure components and demonstrates how seemingly minor protocol handling issues can result in major service disruptions. Security teams should also review their incident response procedures to ensure rapid detection and remediation of similar vulnerabilities in network equipment, particularly within core infrastructure components that manage user sessions and traffic routing functions.