CVE-2016-8701 in potrace
Summary
by MITRE
Heap-based buffer overflow in the bm_readbody_bmp function in bitmap_io.c in potrace before 1.13 allows remote attackers to have unspecified impact via a crafted BMP image, a different vulnerability than CVE-2016-8698, CVE-2016-8699, CVE-2016-8700, CVE-2016-8702, and CVE-2016-8703.
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Analysis
by VulDB Data Team • 08/08/2020
The vulnerability identified as CVE-2016-8701 represents a heap-based buffer overflow in the potrace library's bitmap input/output processing functionality. This flaw exists within the bm_readbody_bmp function located in the bitmap_io.c source file, affecting versions of potrace prior to 1.13. The vulnerability specifically targets the handling of BMP image files during the reading process, creating a condition where maliciously crafted BMP files can trigger memory corruption. This type of vulnerability falls under the CWE-121 heap-based buffer overflow category, which is classified as a critical memory safety issue that can lead to arbitrary code execution or system instability.
The technical exploitation of this vulnerability occurs when potrace processes a specially crafted BMP image file that contains malformed data structures. During the bitmap reading operation, the bm_readbody_bmp function attempts to allocate memory on the heap to store image data, but fails to properly validate the size parameters or bounds of the incoming data. This improper validation allows an attacker to provide input data that exceeds the allocated buffer size, resulting in memory corruption that can overwrite adjacent heap memory regions. The vulnerability is particularly dangerous because it enables remote code execution through crafted BMP files that could be delivered via web browsers, email attachments, or other attack vectors that process bitmap images.
The operational impact of CVE-2016-8701 extends across multiple attack surfaces where potrace is utilized for bitmap processing, including graphic design applications, document conversion tools, and web-based image processing services. Systems that process untrusted BMP image files are at risk, particularly those that automatically convert or display bitmap images without proper input sanitization. The vulnerability's remote exploitation capability means that attackers can trigger the buffer overflow through network-based attacks without requiring local access to the target system. This characteristic aligns with ATT&CK technique T1203, which involves using malicious files to gain remote access to systems. The unspecified impact mentioned in the vulnerability description indicates that the consequences could range from denial of service to full system compromise depending on the execution environment and memory layout.
Mitigation strategies for CVE-2016-8701 focus primarily on updating to potrace version 1.13 or later, which contains the necessary patches to address the heap buffer overflow. Organizations should also implement input validation measures that sanitize BMP file headers and enforce strict bounds checking during image processing operations. Network-based defenses can include content filtering systems that scan for malicious BMP files, particularly those that exhibit suspicious header structures or oversized data segments. Additionally, application developers should employ secure coding practices such as using memory-safe programming languages or libraries, implementing proper bounds checking, and utilizing address space layout randomization to reduce exploitability. The vulnerability demonstrates the importance of maintaining up-to-date software libraries and implementing defense-in-depth strategies that include both perimeter security controls and internal application hardening measures to protect against similar heap-based buffer overflow exploits.