CVE-2018-18409 in tcpflow
Summary
by MITRE
A stack-based buffer over-read exists in setbit() at iptree.h of TCPFLOW 1.5.0, due to received incorrect values causing incorrect computation, leading to denial of service during an address_histogram call or a get_histogram call.
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Analysis
by VulDB Data Team • 05/30/2023
The vulnerability identified as CVE-2018-18409 represents a critical stack-based buffer over-read condition within the TCPFLOW network analysis tool version 1.5.0. This flaw manifests specifically within the setbit() function located in the iptree.h source file, demonstrating a classic example of improper input validation that can lead to severe operational consequences. The vulnerability arises from the tool's failure to properly validate received data values, resulting in incorrect computational logic that ultimately triggers memory access violations. The affected TCPFLOW version operates as a network traffic analysis utility that captures and analyzes tcpdump output, making it a valuable tool for network security professionals while simultaneously presenting a potential attack vector when exploited.
The technical implementation of this vulnerability stems from inadequate boundary checking within the setbit() function, which processes network address information during histogram calculations. When the iptree.h component receives malformed or unexpected input values during address_histogram or get_histogram operations, the computational logic fails to properly validate array indices or buffer limits. This incorrect computation leads to memory access beyond allocated stack space, creating a condition where the program attempts to read from memory locations that may not contain valid data. The over-read behavior specifically occurs during histogram generation processes where the tool maintains internal data structures representing network address ranges and their associated statistical information. According to CWE classification, this vulnerability maps to CWE-126: Buffer Underread, which describes situations where a program reads from a buffer using an index that is outside the valid range of the buffer, leading to information disclosure or system instability.
The operational impact of CVE-2018-18409 extends beyond simple denial of service, as it represents a potential pathway for attackers to disrupt network monitoring operations or potentially extract sensitive information from memory. When exploited, the vulnerability causes TCPFLOW to crash during histogram generation, effectively rendering the tool unusable for network analysis purposes during the affected operations. Network security teams relying on TCPFLOW for traffic analysis and forensic investigations would face significant operational disruption, particularly during high-volume traffic analysis or when processing large datasets. The vulnerability's exploitation requires minimal privileges and can be triggered through malformed network data, making it particularly dangerous in environments where network traffic analysis tools process untrusted data streams. This aligns with ATT&CK technique T1499.001: Network Denial of Service, where adversaries target network infrastructure tools to disrupt availability and compromise operational integrity.
Mitigation strategies for CVE-2018-18409 should prioritize immediate software updates to versions that have addressed the buffer over-read condition, as the vulnerability has been resolved in subsequent releases of TCPFLOW. System administrators should implement input validation measures to filter potentially malicious network data before it reaches the TCPFLOW analysis engine, reducing the attack surface. Additionally, monitoring and alerting systems should be configured to detect abnormal TCPFLOW behavior or process crashes during histogram generation operations, providing early warning of potential exploitation attempts. The vulnerability demonstrates the importance of proper boundary checking and input validation in network analysis tools, particularly those handling large volumes of potentially malicious data streams. Organizations should also consider implementing network segmentation and access controls to limit exposure to untrusted network traffic that could trigger this vulnerability during normal operations.