CVE-2017-7299 in binutils
Summary
by MITRE
The Binary File Descriptor (BFD) library (aka libbfd), as distributed in GNU Binutils 2.28, has an invalid read (of size 8) because the code to emit relocs (bfd_elf_final_link function in bfd/elflink.c) does not check the format of the input file before trying to read the ELF reloc section header. The vulnerability leads to a GNU linker (ld) program crash.
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Analysis
by VulDB Data Team • 12/03/2024
The vulnerability identified as CVE-2017-7299 resides within the Binary File Descriptor library, commonly known as BFD, which is a core component of the GNU Binutils package. This library serves as a fundamental interface for handling various binary file formats, including object files, archives, and executable binaries. The specific flaw manifests in the bfd_elf_final_link function located in the bfd/elflink.c source file, where the code fails to properly validate the input file format before attempting to access ELF reloc section headers. This critical oversight occurs within the GNU linker (ld) program, which relies heavily on BFD for processing and linking binary objects. The vulnerability affects GNU Binutils version 2.28, making it particularly concerning as this version was widely distributed and used across numerous systems and development environments. The improper handling of file format validation creates a scenario where maliciously crafted input files can trigger unexpected behavior in the linking process.
The technical nature of this vulnerability constitutes an invalid memory read operation of 8 bytes in size, which represents a classic buffer over-read condition. This occurs because the code path does not perform adequate checks to ensure that the input file conforms to the expected ELF format before attempting to parse reloc section headers. When the linker encounters a malformed or unexpected file structure, it proceeds to read memory locations that may not contain valid data or may be outside the bounds of allocated memory regions. This type of vulnerability falls under the CWE-125 weakness category, which specifically addresses out-of-bounds read conditions in software implementations. The flaw essentially allows an attacker to manipulate the linking process by providing specially crafted input files that trigger the code path leading to the invalid read operation, ultimately resulting in program termination through a crash condition.
The operational impact of CVE-2017-7299 extends beyond simple program crashes, as it represents a potential denial-of-service vulnerability that can be exploited in automated build environments or continuous integration systems. When the GNU linker encounters a malformed input file, it terminates abruptly, potentially disrupting entire build processes and development workflows. This vulnerability is particularly dangerous in environments where automated linking processes are executed without proper input validation, as it could be leveraged to cause system-wide disruptions. The ATT&CK framework categorizes this type of vulnerability under the 'Execution' phase, specifically within the 'Exploitation of Remote Services' category, as attackers can potentially craft input files that cause the linker to crash when processing them. Additionally, the vulnerability demonstrates characteristics of 'Privilege Escalation' in scenarios where the linker is executed with elevated privileges, as the crash could potentially be exploited to gain additional system access or to cause further instability within the target environment.
Mitigation strategies for CVE-2017-7299 primarily involve upgrading to patched versions of GNU Binutils where the vulnerability has been addressed through proper input validation and format checking before accessing ELF reloc section headers. System administrators should prioritize updating their development environments and build servers to versions of Binutils that contain the necessary fixes. Additionally, implementing input validation at the application level can help prevent malformed files from reaching the linker process, while monitoring and logging mechanisms can help detect unusual linking activities that may indicate exploitation attempts. Organizations should also consider implementing sandboxing techniques for linking operations to limit the potential impact of any successful exploitation attempts. The fix typically involves adding proper format verification checks before accessing section headers, ensuring that the input file structure matches the expected ELF format before attempting to parse reloc information. This approach aligns with the principle of least privilege and defense-in-depth strategies recommended by cybersecurity frameworks such as NIST SP 800-53, which emphasizes the importance of input validation and proper error handling in preventing exploitation of similar vulnerabilities.