CVE-2020-35342 in Binutils
Summary
by MITRE • 08/22/2023
GNU Binutils before 2.34 has an uninitialized-heap vulnerability in function tic4x_print_cond (file opcodes/tic4x-dis.c) which could allow attackers to make an information leak.
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Analysis
by VulDB Data Team • 09/14/2023
The vulnerability identified as CVE-2020-35342 represents a critical uninitialized heap memory issue within GNU Binutils version 2.34 and earlier releases. This flaw exists specifically within the tic4x_print_cond function located in the opcodes/tic4x-dis.c file, which is part of the disassembly functionality used for Texas Instruments C4x architecture processors. The vulnerability arises from improper initialization of heap-allocated memory structures that are subsequently accessed during the disassembly process, creating potential pathways for information disclosure attacks.
The technical nature of this vulnerability stems from the function's failure to properly initialize memory before utilizing it in conditional printing operations. When the disassembler processes certain binary inputs targeting TI C4x architecture, it invokes tic4x_print_cond which operates on heap-allocated data structures without ensuring they contain valid initial values. This uninitialized memory state can contain residual data from previous operations, potentially exposing sensitive information from other parts of the application's memory space. The flaw falls under CWE-457 which specifically addresses the use of uninitialized variables, and more broadly aligns with CWE-248 which covers exposure of uninitialized memory.
From an operational perspective, this vulnerability presents significant risks to systems utilizing GNU Binutils for disassembly tasks, particularly in security-sensitive environments where binary analysis is performed on potentially malicious inputs. Attackers could exploit this weakness by crafting specific input files that trigger the vulnerable code path, potentially leading to information leakage that might reveal memory contents, cryptographic keys, or other sensitive data. The impact is particularly concerning in contexts where binutils is used for malware analysis, security auditing, or reverse engineering activities where the tool might process untrusted binary data.
The vulnerability's exploitation requires a specific code path involving the disassembly of TI C4x architecture binaries through the affected function, making it less broadly applicable than some other memory corruption vulnerabilities but still significant within its targeted scope. The information leak aspect means that while the vulnerability may not directly enable arbitrary code execution, it can provide attackers with valuable insights into memory layouts and potentially sensitive data structures. Organizations should consider implementing mitigations such as updating to GNU Binutils 2.34 or later versions where this issue has been resolved, and applying additional input validation measures when processing binary data through disassembly tools. The ATT&CK framework categorizes this under technique T1059 for execution and T1557 for defense evasion, as the information leak could be used to bypass security controls or aid in further exploitation efforts.
This vulnerability demonstrates the importance of proper memory initialization practices in security-critical software components and highlights how seemingly minor initialization errors can create significant information disclosure risks. The fix implemented in GNU Binutils 2.34 ensures that heap memory is properly initialized before use, preventing the leakage of uninitialized data to attackers. System administrators and security teams should prioritize updating affected systems and monitoring for potential exploitation attempts that might leverage this information leak vulnerability.