CVE-2003-0033 in Snort
Summary
by MITRE
Buffer overflow in the RPC preprocessor for Snort 1.8 and 1.9.x before 1.9.1 allows remote attackers to execute arbitrary code via fragmented RPC packets.
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Analysis
by VulDB Data Team • 10/28/2024
The vulnerability identified as CVE-2003-0033 represents a critical buffer overflow flaw within the Remote Procedure Call preprocessor of Snort intrusion detection system versions 1.8 and 1.9.x prior to 1.9.1. This vulnerability specifically targets the handling of fragmented RPC packets, creating a potential pathway for remote code execution. The issue stems from inadequate input validation and memory management within the RPC processing module, which fails to properly handle oversized or malformed packet fragments that exceed allocated buffer boundaries.
The technical implementation of this vulnerability exploits the way Snort processes fragmented network packets during RPC protocol inspection. When the system receives RPC packets that have been fragmented across multiple network frames, the preprocessor attempts to reassemble these fragments without sufficient boundary checking. This flaw falls under CWE-121, which describes stack-based buffer overflow conditions, and more specifically aligns with CWE-787, representing out-of-bounds write operations. The vulnerability creates a scenario where an attacker can craft specially designed RPC fragments that, when processed by the affected Snort versions, cause the application to write data beyond the allocated memory space, potentially overwriting critical program structures or executable code.
The operational impact of this vulnerability extends beyond simple system compromise, as it allows remote attackers to execute arbitrary code with the privileges of the Snort process. This presents a significant risk to network security infrastructure since Snort typically runs with elevated privileges to monitor and analyze network traffic effectively. The attack vector requires only the ability to send fragmented RPC packets to the target system, making it particularly dangerous in environments where Snort is deployed as a network monitoring tool. According to ATT&CK framework category T1059, this vulnerability enables remote code execution through system services, while T1133 covers the exploitation of network protocols to gain unauthorized access.
Mitigation strategies for this vulnerability require immediate patching of affected Snort installations to version 1.9.1 or later, which includes proper bounds checking and memory management for RPC packet processing. Network administrators should also implement additional defensive measures such as disabling RPC inspection rules when not actively needed, implementing proper network segmentation to limit exposure, and deploying network access controls to restrict traffic to only necessary RPC ports. The vulnerability demonstrates the importance of robust input validation in network security tools and highlights the critical need for regular security updates in intrusion detection systems. Organizations should also consider implementing network monitoring to detect unusual fragmentation patterns that might indicate exploitation attempts, as well as maintaining detailed logging of RPC traffic for forensic analysis purposes.