CVE-2018-10534 in binutils
Summary
by MITRE
The _bfd_XX_bfd_copy_private_bfd_data_common function in peXXigen.c in the Binary File Descriptor (BFD) library (aka libbfd), as distributed in GNU Binutils 2.30, processes a negative Data Directory size with an unbounded loop that increases the value of (external_IMAGE_DEBUG_DIRECTORY) *edd so that the address exceeds its own memory region, resulting in an out-of-bounds memory write, as demonstrated by objcopy copying private info with _bfd_pex64_bfd_copy_private_bfd_data_common in pex64igen.c.
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Analysis
by VulDB Data Team • 03/08/2023
The vulnerability described in CVE-2018-10534 resides within the Binary File Descriptor (BFD) library component of GNU Binutils version 2.30, specifically manifesting in the _bfd_XX_bfd_copy_private_bfd_data_common function located in peXXigen.c. This flaw represents a critical memory safety issue that occurs during the processing of Portable Executable (PE) files, particularly when objcopy attempts to copy private BFD data. The vulnerability stems from inadequate input validation and boundary checking mechanisms within the BFD library's handling of Data Directory structures, which are fundamental components of PE file format specifications. The affected function processes a negative Data Directory size parameter that should never occur under normal circumstances, yet the code fails to properly validate this condition before proceeding with memory operations.
The technical execution of this vulnerability involves an unbounded loop that continuously increments the value of (external_IMAGE_DEBUG_DIRECTORY) *edd, causing the memory address to exceed its allocated memory region boundaries. This type of memory corruption represents a classic out-of-bounds write condition that can lead to arbitrary code execution or system instability. The flaw specifically affects the pex64igen.c file's _bfd_pex64_bfd_copy_private_bfd_data_common function, which is part of the 64-bit PE file processing pipeline. When objcopy encounters a malformed PE file with negative Data Directory size values, the loop continues indefinitely, causing memory corruption that can overwrite adjacent memory regions and potentially execute malicious code.
The operational impact of this vulnerability extends beyond simple memory corruption, as it can be exploited by attackers to achieve arbitrary code execution within the context of the application that processes the malicious PE file. This vulnerability is particularly dangerous because it affects a core library component used by numerous tools including objcopy, which is widely used in software development, system administration, and security analysis workflows. The vulnerability can be triggered through the simple act of processing a specially crafted PE file, making it an attractive target for exploitation in scenarios where automated file processing occurs. From an attack perspective, this vulnerability aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter: PowerShell and T1553.004 for Credential Access: File and Directory Permissions Modification, as it enables privilege escalation through code execution. The underlying CWE classification for this vulnerability is CWE-121, which describes Stack-based Buffer Overflow, although the specific implementation involves heap memory corruption due to the nature of the BFD library's memory management.
Mitigation strategies for CVE-2018-10534 should prioritize immediate patching of GNU Binutils to version 2.31 or later, where the vulnerability has been resolved through proper input validation and boundary checking mechanisms. Organizations should implement strict file validation procedures before processing PE files through tools like objcopy, particularly in automated environments where untrusted input is common. Network security controls should include signature-based detection for known malicious PE files that trigger this vulnerability, while endpoint protection solutions should monitor for unusual memory access patterns that may indicate exploitation attempts. Additionally, system administrators should consider implementing privilege separation measures, ensuring that tools processing potentially malicious files operate with minimal required privileges to limit potential damage from successful exploitation attempts. The fix implemented in the patched versions addresses the root cause by adding proper validation of Data Directory size parameters and implementing bounds checking to prevent the unbounded loop from occurring.