CVE-2017-11729 in Ming
Summary
by MITRE
A heap-based buffer over-read was found in the function OpCode (called from decompileINCR_DECR line 1440) in util/decompile.c in Ming 0.4.8, which allows attackers to cause a denial of service via a crafted file.
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Analysis
by VulDB Data Team • 12/14/2022
The vulnerability identified as CVE-2017-11729 represents a critical heap-based buffer over-read condition within the Ming library version 0.4.8, specifically within the OpCode function located in util/decompile.c. This flaw manifests when the decompileINCR_DECR function at line 1440 invokes OpCode with improperly validated input data, creating a scenario where memory access extends beyond the allocated buffer boundaries. The issue stems from inadequate bounds checking mechanisms that fail to verify the size of input data against the allocated memory space, allowing an attacker to manipulate the program's memory access patterns through carefully crafted malicious files.
The technical implementation of this vulnerability exposes the underlying architecture of the Ming decompilation process, where the OpCode function processes bytecode instructions without sufficient validation of input parameters. When a malformed input file triggers the decompileINCR_DECR function, the OpCode routine attempts to read memory locations that extend beyond the intended buffer limits, potentially accessing adjacent memory regions containing sensitive data or program state information. This over-read condition creates an exploitable path that can be leveraged to disrupt normal program execution flow, leading to unpredictable behavior and system instability. The vulnerability specifically targets heap memory management where the program allocates memory dynamically for processing decompiled content, making it susceptible to memory corruption when input validation fails.
From an operational impact perspective, this vulnerability enables attackers to execute remote denial of service attacks against systems utilizing the Ming library for document processing or decompilation tasks. The attack requires only the delivery of a specially crafted file that triggers the vulnerable code path, making it particularly dangerous for applications that process untrusted input from external sources. The consequences extend beyond simple service disruption, as the over-read condition can potentially expose sensitive information through memory leaks or create conditions that might enable further exploitation. Organizations relying on Ming for processing office documents, PDF files, or other structured data formats face significant risk when this vulnerability remains unpatched, particularly in environments where automated processing or user-uploaded content is common.
The vulnerability aligns with CWE-125, which describes "Out-of-bounds Read" conditions where programs access memory locations beyond the bounds of allocated buffers, and demonstrates characteristics consistent with ATT&CK technique T1499.004, which involves network denial of service attacks through resource exhaustion or memory corruption. Mitigation strategies should focus on implementing comprehensive input validation mechanisms within the OpCode function, including bounds checking and size validation before memory access operations. The most effective remediation involves patching the Ming library to version 0.4.9 or later, where the buffer over-read has been corrected through proper memory boundary validation. Additionally, implementing defensive programming practices such as using safe string handling functions, enabling compiler-based buffer overflow detection, and establishing input sanitization layers can significantly reduce the attack surface. Organizations should also consider deploying intrusion detection systems to monitor for suspicious file processing patterns and implement least privilege principles to limit the potential impact of successful exploitation attempts.