CVE-2010-2820 in Firewall Services Module Software
Summary
by MITRE
Unspecified vulnerability in the SunRPC inspection feature on the Cisco Firewall Services Module (FWSM) with software 3.1 before 3.1(17.2), 3.2 before 3.2(16.1), 4.0 before 4.0(10.1), and 4.1 before 4.1(1.1) for Catalyst 6500 series switches and 7600 series routers allows remote attackers to cause a denial of service (device reload) via crafted SunRPC messages, aka Bug ID CSCte61662.
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Analysis
by VulDB Data Team • 03/03/2017
The vulnerability described in CVE-2010-2820 represents a critical flaw in the SunRPC inspection capabilities of Cisco Firewall Services Module FWSM devices. This issue affects multiple software versions including 3.1.x before 3.1(17.2), 3.2.x before 3.2(16.1), 4.0.x before 4.0(10.1), and 4.1.x before 4.1(1.1) running on Catalyst 6500 and 7600 series network infrastructure. The vulnerability specifically targets the inspection mechanism responsible for processing SunRPC protocol traffic, which is commonly used for remote procedure calls in distributed computing environments.
The technical flaw manifests when the FWSM device processes malformed or crafted SunRPC messages that exploit an unspecified condition within the inspection engine. This processing error leads to an unrecoverable system state where the device becomes unable to continue normal operations and subsequently undergoes an automatic reload or reboot. The vulnerability operates at the protocol inspection layer, meaning it affects how the firewall module analyzes and processes network traffic rather than exploiting application-level flaws or network layer vulnerabilities.
From an operational perspective, this vulnerability presents a significant risk to network availability and business continuity. Remote attackers can leverage this weakness to execute denial of service attacks against critical network infrastructure without requiring authentication or privileged access. The impact extends beyond simple service disruption as the device reload process can result in temporary network outages, potential data loss during the restart process, and service interruptions for dependent network applications. Network administrators face the challenge of maintaining uptime while applying patches, as the vulnerability can be exploited by attackers anywhere on the internet.
The attack surface for this vulnerability is particularly concerning given the widespread deployment of Cisco FWSM modules in enterprise and service provider networks. The ability to remotely trigger device reboots without authentication makes this a high-value target for malicious actors seeking to disrupt network operations. This vulnerability aligns with ATT&CK technique T1499.004 for network disruption and represents a classic example of a privilege escalation vector that can be exploited by unauthenticated remote attackers. Organizations should implement network segmentation to limit exposure, monitor for suspicious SunRPC traffic patterns, and maintain current software versions to prevent exploitation. The vulnerability also demonstrates the importance of proper input validation and error handling in network security appliances, as detailed in CWE category 20 for improper input validation.
Cisco has released patches addressing this vulnerability in the affected software versions, and network administrators should immediately apply the recommended security updates to mitigate the risk of exploitation. The vulnerability highlights the need for comprehensive security testing of protocol inspection mechanisms and the importance of maintaining up-to-date security configurations across network infrastructure devices. Organizations should also consider implementing intrusion detection systems to monitor for potential exploitation attempts and establish incident response procedures to address successful attacks against affected systems.