CVE-2019-6439 in wolfSSL
Summary
by MITRE
examples/benchmark/tls_bench.c in a benchmark tool in wolfSSL through 3.15.7 has a heap-based buffer overflow.
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Analysis
by VulDB Data Team • 07/01/2023
The vulnerability identified as CVE-2019-6439 resides within the wolfSSL benchmark tool, specifically in the examples/benchmark/tls_bench.c file, affecting versions through 3.15.7. This heap-based buffer overflow represents a critical security flaw that could potentially allow attackers to execute arbitrary code or cause denial of service conditions. The benchmark tool is designed to measure cryptographic performance and TLS handshake capabilities, making it a valuable utility for developers and system administrators. However, the buffer overflow vulnerability in this component creates a potential attack surface that could be exploited in environments where the benchmark tool is executed with elevated privileges or in automated testing scenarios.
The technical flaw manifests as a heap-based buffer overflow occurring in the tls_bench.c file, which suggests that the application fails to properly validate input lengths before copying data into allocated memory buffers. This type of vulnerability typically arises when developers assume a maximum buffer size for input data without implementing proper bounds checking mechanisms. The CWE-121 classification applies here as this represents a classic stack-based buffer overflow condition that has been extended to heap memory management, where insufficient bounds checking allows attackers to overwrite adjacent memory regions. The vulnerability could be triggered through malformed input parameters or crafted test data that exceeds the allocated buffer capacity during the TLS benchmarking process.
The operational impact of CVE-2019-6439 extends beyond simple denial of service scenarios, as heap-based buffer overflows can potentially enable remote code execution when the vulnerable application is run with sufficient privileges. In environments where wolfSSL benchmark tools are regularly executed as part of automated testing pipelines or security audits, this vulnerability could serve as a foothold for more sophisticated attacks. The attacker would need to craft specific input data that causes the buffer overflow during the TLS benchmark execution, potentially leading to memory corruption that could be exploited to gain control over the executing process. This vulnerability is particularly concerning in continuous integration environments where benchmarking tools are automatically invoked.
Mitigation strategies for CVE-2019-6439 should focus on immediate version upgrades to wolfSSL 4.0.0 or later, where the buffer overflow has been addressed through proper bounds checking and memory management practices. System administrators should also implement input validation controls to prevent malformed data from reaching the vulnerable code paths, while monitoring for suspicious execution patterns that might indicate exploitation attempts. The ATT&CK framework's T1059.007 technique for command and script injection should be considered when monitoring for potential exploitation attempts, as attackers may attempt to leverage this vulnerability through automated benchmarking processes. Additionally, implementing proper memory protection mechanisms such as stack canaries and address space layout randomization can provide additional defense-in-depth measures against potential exploitation attempts.