CVE-2021-1285 in UTD SNORT IPS Engine Software
Summary
by MITRE • 11/18/2024
Multiple Cisco products are affected by a vulnerability in the Ethernet Frame Decoder of the Snort detection engine that could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition. The vulnerability is due to improper handling of error conditions when processing Ethernet frames. An attacker could exploit this vulnerability by sending malicious Ethernet frames through an affected device. A successful exploit could allow the attacker to exhaust disk space on the affected device, which could result in administrators being unable to log in to the device or the device being unable to boot up correctly.Note: Manual intervention is required to recover from this situation. Customers are advised to contact the Cisco Technical Assistance Center (TAC) to help recover a device in this condition.Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.
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Analysis
by VulDB Data Team • 11/18/2024
This vulnerability resides within the Ethernet Frame Decoder component of Cisco's Snort detection engine implementation, representing a critical denial of service flaw that affects multiple Cisco network devices. The vulnerability stems from inadequate error condition handling during Ethernet frame processing, creating a scenario where an unauthenticated attacker positioned within the same network segment can manipulate device behavior through crafted frame transmission. This weakness falls under the CWE-399 category of Resource Management Errors, specifically manifesting as insufficient resource exhaustion protection during network packet processing operations.
The technical exploitation mechanism involves sending maliciously constructed Ethernet frames to an affected Cisco device, which then processes these frames through the vulnerable Snort detection engine component. When the Ethernet Frame Decoder encounters malformed or specially crafted frames, it fails to properly handle the resulting error conditions, leading to progressive disk space exhaustion on the affected device. This process operates at the network layer where the device's storage resources become consumed through repeated processing of malformed frames, ultimately causing the system to become unresponsive and preventing normal administrative access or device boot operations.
The operational impact of this vulnerability extends beyond simple service disruption to encompass complete system unreliability and potential administrative lockdown conditions. Network administrators face the challenging scenario where device recovery requires manual intervention and direct assistance from Cisco Technical Assistance Center personnel, as no automated recovery mechanisms exist for this specific vulnerability condition. The vulnerability affects the fundamental availability of network infrastructure, potentially compromising network security monitoring capabilities and creating operational downtime that could impact business continuity. This represents a significant concern for enterprise networks where network monitoring systems are critical for security operations and where unauthorized access to network segments could enable exploitation.
Cisco has addressed this vulnerability through targeted software updates that modify the Ethernet Frame Decoder's error handling procedures to properly manage malformed frame conditions without consuming excessive system resources. The absence of workarounds indicates that the vulnerability's exploitation method directly targets core processing functions that cannot be mitigated through configuration changes or network segmentation approaches. Organizations should prioritize applying these security updates immediately to prevent potential exploitation, as the vulnerability's impact severity aligns with the ATT&CK framework's T1499.004 technique for network denial of service attacks, where adversaries leverage system resource exhaustion to compromise availability. The vulnerability demonstrates how network security tools themselves can become attack vectors when proper input validation and error handling procedures are not implemented, emphasizing the importance of secure coding practices in network infrastructure components.