CVE-2018-20458 in radare2
Summary
by MITRE
In radare2 prior to 3.1.1, r_bin_dyldcache_extract in libr/bin/format/mach0/dyldcache.c may allow attackers to cause a denial-of-service (application crash caused by out-of-bounds read) by crafting an input file.
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Analysis
by VulDB Data Team • 06/22/2023
The vulnerability CVE-2018-20458 represents a critical out-of-bounds read flaw in radare2 version 3.1.0 and earlier, specifically within the dyldcache extraction functionality of the binary analysis framework. This issue resides in the r_bin_dyldcache_extract function located in libr/bin/format/mach0/dyldcache.c, which is responsible for processing dynamic loader cache files on macOS and iOS systems. The flaw occurs when radare2 attempts to parse malformed or specially crafted dyldcache input files, leading to memory access violations that can result in application crashes and complete denial-of-service conditions.
The technical implementation of this vulnerability stems from insufficient input validation and boundary checking within the dyldcache parsing logic. When processing maliciously constructed input files, the function fails to properly validate array indices or buffer limits before accessing memory locations, creating a classic out-of-bounds read condition. This type of vulnerability falls under CWE-129, which specifically addresses insufficient validation of length of inputs, and represents a subset of the broader CWE-125 vulnerability category for out-of-bounds read conditions. The flaw demonstrates poor defensive programming practices where the software assumes valid input without proper validation mechanisms.
From an operational perspective, this vulnerability presents significant risks to security researchers and analysts who rely on radare2 for reverse engineering and malware analysis tasks. Attackers can exploit this weakness by crafting specially formatted dyldcache files that trigger the out-of-bounds read when loaded into radare2, causing the application to crash and potentially exposing the system to further exploitation. The impact extends beyond simple denial-of-service as the crash behavior could be leveraged in more sophisticated attacks, particularly in environments where automated analysis tools rely on radare2 for processing potentially malicious samples. This vulnerability directly impacts the ATT&CK technique T1059.007 for Command and Scripting Interpreter, as it can be used to disrupt automated analysis workflows and compromise the integrity of binary analysis processes.
The mitigation strategy for CVE-2018-20458 requires immediate upgrading to radare2 version 3.1.1 or later, which includes proper bounds checking and input validation fixes. Organizations should also implement defensive measures such as input sanitization for any dyldcache files processed through radare2, and consider deploying additional monitoring to detect abnormal application behavior during binary analysis operations. Security teams should prioritize patching this vulnerability in environments where radare2 is actively used for security research, malware analysis, or penetration testing activities, as the flaw could be exploited to disrupt critical security operations and analysis workflows.