CVE-2017-8396 in binutils
Summary
by MITRE
The Binary File Descriptor (BFD) library (aka libbfd), as distributed in GNU Binutils 2.28, is vulnerable to an invalid read of size 1 because the existing reloc offset range tests didn't catch small negative offsets less than the size of the reloc field. This vulnerability causes programs that conduct an analysis of binary programs using the libbfd library, such as objdump, to crash.
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Analysis
by VulDB Data Team • 12/04/2024
The vulnerability identified as CVE-2017-8396 resides within the Binary File Descriptor library, commonly known as BFD or libbfd, which is a core component of the GNU Binutils suite used extensively for handling binary files and object code manipulation. This particular flaw manifests in version 2.28 of the Binutils distribution, where the library fails to properly validate reloc offset values during binary analysis operations. The issue specifically affects programs that rely on libbfd for examining binary executables, including the widely used objdump utility that performs disassembly and analysis of object files. The vulnerability stems from insufficient boundary checking mechanisms within the relocation processing code, creating a scenario where certain malformed binary inputs can trigger unexpected behavior.
The technical exploitation of this vulnerability occurs through a specific memory access pattern where the BFD library attempts to read a single byte from an invalid memory location. This happens because the existing range validation tests for relocation offsets are inadequate in covering negative offset values that fall below the size of the relocation field itself. When processing binary files containing such malformed relocation entries, the library executes an invalid read operation of size 1, which fundamentally violates memory safety principles. This particular flaw represents a classic case of improper input validation and memory boundary checking, aligning with CWE-129 which addresses issues related to insufficient validation of length of input buffers. The vulnerability demonstrates how seemingly minor oversights in range checking can lead to critical security implications in widely used system utilities.
The operational impact of CVE-2017-8396 extends beyond simple program crashes, as it affects the reliability and security of numerous security analysis tools and development environments that depend on the BFD library. When objdump or similar utilities encounter malformed binary inputs, they experience segmentation faults or undefined behavior, effectively rendering these analysis tools unreliable for security assessments, malware analysis, or reverse engineering tasks. This vulnerability can be particularly problematic in automated security scanning systems where the tools may encounter unexpected binary formats during routine analysis. The crash behavior also creates potential denial of service conditions, as adversaries could craft malicious binary files designed to cause analysis tools to fail, thereby preventing legitimate security investigations. From an ATT&CK framework perspective, this vulnerability could be leveraged in initial access or execution phases where adversaries might attempt to disrupt security analysis operations or use the instability to mask malicious activities.
Mitigation strategies for CVE-2017-8396 primarily involve upgrading to patched versions of GNU Binutils where the BFD library has been updated to include proper validation of relocation offset values. System administrators and security professionals should prioritize updating their development and security analysis toolchains to versions that address this specific memory access violation. Additionally, implementing defensive programming practices such as input sanitization and boundary checking in applications that interface with BFD directly can provide additional protection layers. The vulnerability highlights the importance of comprehensive testing for edge cases in memory management operations, particularly when dealing with low-level binary file formats. Organizations should also consider implementing runtime monitoring and intrusion detection systems to identify potential exploitation attempts targeting this class of vulnerabilities in their security infrastructure.