CVE-2020-24266 in tcpprep
Summary
by MITRE • 10/19/2020
An issue was discovered in tcpreplay tcpprep v4.3.3. There is a heap buffer overflow vulnerability in get_l2len() that can make tcpprep crash and cause a denial of service.
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Analysis
by VulDB Data Team • 11/21/2020
The vulnerability identified as CVE-2020-24266 represents a critical heap buffer overflow condition within the tcpreplay tcpprep utility version 4.3.3. This flaw resides in the get_l2len() function which processes network packet data during packet replay operations. The issue manifests when the application encounters malformed or specially crafted network packets that exceed expected buffer boundaries during layer 2 header length calculations. Such buffer overflows typically occur when input validation is insufficient and the application writes data beyond the allocated memory space, potentially leading to unpredictable application behavior including crashes and system instability.
The technical exploitation of this vulnerability requires an attacker to provide malicious packet data that triggers the buffer overflow condition within the get_l2len() function. This function is responsible for determining the length of layer 2 headers in network packets, and when processing improperly formatted packets, it fails to properly validate input parameters before performing memory operations. The heap buffer overflow specifically occurs in the dynamic memory allocation context where the application attempts to write beyond the allocated buffer boundaries, potentially corrupting adjacent heap memory regions and causing memory management structures to become inconsistent. This type of vulnerability falls under CWE-121 heap-based buffer overflow classification and represents a classic memory safety issue that can be exploited to cause denial of service or potentially achieve arbitrary code execution depending on memory layout and exploitation conditions.
The operational impact of this vulnerability extends beyond simple denial of service scenarios as it affects the reliability and availability of network analysis and packet replay systems that depend on tcpreplay tcpprep functionality. Organizations utilizing this tool for network security testing, packet capture analysis, or network traffic replay operations face potential disruption when encountering malicious or malformed packet data. The vulnerability is particularly concerning in environments where automated packet processing occurs, as it can lead to uncontrolled application termination and service interruption. Attackers could leverage this weakness to systematically crash network monitoring systems, packet analysis tools, or security testing frameworks that employ tcpprep as part of their operational workflow. The vulnerability aligns with ATT&CK technique T1499.004 for network denial of service attacks and represents a significant risk to network infrastructure integrity and operational continuity.
Mitigation strategies for CVE-2020-24266 should prioritize immediate patching of affected systems with the latest stable versions of tcpreplay that contain fixed implementations of the get_l2len() function. System administrators should implement network monitoring to detect potential exploitation attempts and establish automated alerting for application crash events. Input validation controls should be strengthened at network packet processing layers to prevent malformed data from reaching vulnerable functions, while also implementing memory safety mechanisms such as address sanitizer instrumentation and heap integrity checks. Organizations should also consider deploying network segmentation and access controls to limit exposure of systems running tcpprep to untrusted packet data sources. Additionally, regular security assessments of network analysis tools and packet processing utilities should be conducted to identify similar vulnerabilities in the broader network security toolchain. The fix for this vulnerability demonstrates the importance of robust input validation and memory management practices in network security applications, aligning with industry best practices for secure coding and defensive programming techniques that prevent buffer overflow conditions in critical infrastructure software.