CVE-2019-12972 in binutils
Summary
by MITRE
An issue was discovered in the Binary File Descriptor (BFD) library (aka libbfd), as distributed in GNU Binutils 2.32. There is a heap-based buffer over-read in _bfd_doprnt in bfd.c because elf_object_p in elfcode.h mishandles an e_shstrndx section of type SHT_GROUP by omitting a trailing '\0' character.
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Analysis
by VulDB Data Team • 10/08/2023
The vulnerability identified as CVE-2019-12972 resides within the Binary File Descriptor library, commonly known as BFD, which is a core component of the GNU Binutils suite. This library serves as a foundational element for handling various binary file formats including object files, archives, and executable binaries across different architectures. The flaw manifests in the _bfd_doprnt function within the bfd.c file, which processes formatted output operations for binary data structures. The issue specifically impacts GNU Binutils version 2.32, making it a significant concern for systems utilizing this particular version of the toolchain. The vulnerability represents a heap-based buffer over-read condition that can potentially lead to information disclosure, system instability, or arbitrary code execution depending on the exploitation context.
The technical root cause of this vulnerability stems from improper handling of ELF (Executable and Linkable Format) section headers within the elfcode.h file. Specifically, when processing sections of type SHT_GROUP, the elf_object_p function fails to correctly manage the e_shstrndx section by omitting a crucial trailing null character. This omission creates a scenario where the _bfd_doprnt function attempts to read beyond the allocated heap buffer boundaries when processing group sections within ELF binaries. The missing null termination character disrupts the expected string handling operations, causing the buffer over-read to occur during format string processing. This flaw exemplifies a classic buffer management error where insufficient bounds checking allows for memory access beyond intended limits, creating potential attack vectors for malicious actors.
The operational impact of CVE-2019-12972 extends across multiple domains where GNU Binutils is utilized for binary analysis, compilation, linking, and file processing operations. Systems that process untrusted binary inputs through BFD functions become vulnerable to potential exploitation, particularly those employing automated binary analysis tools, compiler toolchains, or security scanning applications that rely on the affected library. The vulnerability can be triggered when processing ELF files containing specially crafted SHT_GROUP sections, making it particularly dangerous in environments where users might encounter or process unknown binary files from untrusted sources. Attackers could potentially exploit this weakness to extract sensitive memory contents, cause denial of service conditions, or in more sophisticated scenarios, leverage the information disclosure to facilitate additional attacks within the system.
Mitigation strategies for this vulnerability should focus on immediate remediation through version updates to GNU Binutils 2.33 or later, which contain the necessary patches to address the buffer over-read condition. Organizations should prioritize updating their toolchains and development environments to eliminate exposure to this flaw. Additionally, implementing proper input validation and sanitization measures when processing binary files can help reduce the attack surface. Security teams should monitor their systems for any instances where BFD functions are called with untrusted input, particularly in automated analysis pipelines or sandboxed environments. The vulnerability aligns with CWE-125, which describes out-of-bounds read conditions, and can be mapped to ATT&CK techniques involving execution through system binaries and privilege escalation through memory corruption vulnerabilities. Regular security assessments and vulnerability scanning should include checks for affected GNU Binutils installations to ensure comprehensive protection against this and similar heap-based buffer over-read issues.