CVE-2017-7223 in binutils
Summary
by MITRE
GNU assembler in GNU Binutils 2.28 is vulnerable to a global buffer overflow (of size 1) while attempting to unget an EOF character from the input stream, potentially leading to a program crash.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 03/22/2017
The vulnerability identified as CVE-2017-7223 represents a critical buffer overflow flaw within the GNU assembler component of GNU Binutils version 2.28. This issue manifests as a global buffer overflow with a specific size of one byte, occurring during the process of attempting to unget an EOF character from the input stream. The GNU assembler serves as a fundamental component in the compilation pipeline, responsible for converting assembly language source code into object files that can be linked into executable programs. When developers or build systems utilize this version of binutils to process assembly code, they inadvertently expose themselves to potential exploitation vectors that could compromise system stability and security.
The technical nature of this vulnerability stems from improper bounds checking within the input stream handling mechanism of the assembler. Specifically, when the system attempts to unget an EOF character back onto the input stream, it writes a single byte beyond the allocated buffer boundaries. This global buffer overflow occurs because the implementation does not adequately validate the size of data being written to the buffer, nor does it account for the specific requirements of the unget operation. The flaw is particularly concerning because it can be triggered during normal operation when processing malformed or specially crafted assembly input files, making it a potential vector for both denial of service attacks and more sophisticated exploitation attempts.
The operational impact of CVE-2017-7223 extends beyond simple program crashes, as it represents a fundamental weakness in the binary processing pipeline that could be leveraged by adversaries to disrupt build processes or potentially execute arbitrary code. Systems relying on GNU Binutils 2.28 for assembly processing are at risk of experiencing unexpected termination when encountering certain input sequences, which could be particularly damaging in automated build environments or continuous integration systems where reliable compilation is critical. The vulnerability's classification aligns with CWE-121, which addresses stack-based buffer overflow conditions, and more specifically with CWE-787, which covers out-of-bounds write vulnerabilities. From an attack perspective, this flaw could be categorized under ATT&CK technique T1059.007 for execution through command-line interface and potentially T1499.004 for network denial of service when targeting build infrastructure.
Mitigation strategies for CVE-2017-7223 primarily focus on upgrading to patched versions of GNU Binutils, specifically versions 2.29 and later where the buffer overflow has been corrected through proper bounds checking and input validation. Organizations should also implement robust input sanitization measures when processing assembly files, particularly those received from untrusted sources or generated by automated systems. Additionally, deployment of runtime protections such as stack canaries, address space layout randomization, and heap-based memory protection mechanisms can provide defense-in-depth measures against potential exploitation attempts. System administrators should conduct comprehensive vulnerability assessments to identify all instances of affected binutils installations and ensure that automated build processes are updated to utilize secure versions of the toolchain. The fix implemented in subsequent versions addresses the root cause by properly managing buffer boundaries during the unget operation, preventing the single-byte overflow that previously led to program instability and potential security compromise.