CVE-2018-8809 in radare2
Summary
by MITRE
In radare2 2.4.0, there is a heap-based buffer over-read in the dalvik_op function of anal_dalvik.c. Remote attackers could leverage this vulnerability to cause a denial of service via a crafted dex file.
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Analysis
by VulDB Data Team • 02/22/2023
The vulnerability identified as CVE-2018-8809 represents a heap-based buffer over-read flaw in radare2 version 2.4.0 within the dalvik_op function of the anal_dalvik.c file. This issue specifically affects the analysis of android dex files through the dalvik bytecode analysis module. The flaw occurs when processing malformed or crafted dex files that contain improperly structured dalvik opcodes, leading to memory access violations beyond the allocated buffer boundaries. Such buffer over-read conditions typically arise from inadequate bounds checking during the parsing of structured binary data formats where the parser assumes certain data lengths or structures without proper validation.
The technical implementation of this vulnerability stems from insufficient input validation within the dalvik bytecode analysis engine. When radare2 encounters a dex file containing maliciously crafted opcodes, the dalvik_op function fails to properly validate array indices or buffer limits before accessing memory locations. This type of flaw falls under CWE-125, which describes out-of-bounds read vulnerabilities, and can be classified as a memory safety issue within the context of the ATT&CK framework under the technique of privilege escalation through software exploitation. The vulnerability specifically targets the analysis component of the tool rather than its core functionality, making it particularly dangerous in automated analysis scenarios where malicious files might be processed without manual oversight.
The operational impact of CVE-2018-8809 manifests primarily as a denial of service condition that can be remotely triggered by sending a specially crafted dex file to a system running vulnerable radare2 software. Attackers can leverage this vulnerability to crash the analysis process, potentially causing the entire reverse engineering workflow to terminate unexpectedly. This denial of service can be particularly problematic in automated malware analysis environments, security research platforms, or any scenario where radare2 is used to process untrusted binary content. The vulnerability does not appear to enable arbitrary code execution or information disclosure, but rather represents a reliability issue that can disrupt legitimate analysis activities and potentially be exploited for more sophisticated attacks if combined with other vulnerabilities in the analysis pipeline.
Mitigation strategies for CVE-2018-8809 should focus on immediate software updates to radare2 version 2.4.1 or later, which contains the necessary patches to address the buffer over-read condition. Organizations should also implement defensive measures such as validating input files through multiple analysis layers before processing with radare2, utilizing sandboxed environments for dex file analysis, and implementing proper error handling routines that can gracefully manage malformed input data. Additionally, security teams should consider implementing network-based detection mechanisms to identify and block suspicious dex file traffic that might be attempting to exploit this vulnerability. The fix typically involves adding proper bounds checking and input validation within the dalvik_op function to ensure that all memory accesses remain within allocated buffer boundaries, thereby preventing the heap-based buffer over-read condition that enables the denial of service attack vector.