CVE-2016-8698 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-2016-8699, CVE-2016-8700, CVE-2016-8701, CVE-2016-8702, and CVE-2016-8703.
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Analysis
by VulDB Data Team • 08/08/2020
The vulnerability identified as CVE-2016-8698 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 prior to 1.13 of the potrace software. The potrace library serves as a tool for tracing bitmaps into vector graphics, commonly used in graphic design applications and document processing systems. The vulnerability specifically manifests when processing crafted BMP image files, making it particularly dangerous in environments where users might encounter untrusted bitmap content. This issue demonstrates the critical importance of proper input validation in graphics processing libraries that handle user-supplied binary data formats.
The technical implementation of this vulnerability stems from inadequate bounds checking within the bitmap reading routine. When the bm_readbody_bmp function processes a maliciously constructed BMP file, it fails to properly validate the size parameters of heap-allocated buffers before copying data into them. This allows attackers to write beyond the allocated memory boundaries, potentially corrupting adjacent heap memory regions. The heap-based nature of the overflow means that the attack can manipulate heap metadata, leading to potential arbitrary code execution or denial of service conditions. The vulnerability operates at the intersection of memory corruption and input parsing, where the attacker controls the input structure to force improper memory operations. According to CWE classification, this maps to CWE-121, heap-based buffer overflow, which is a well-documented category of memory safety issues that frequently leads to system compromise.
The operational impact of CVE-2016-8698 extends beyond simple exploitation capabilities, as it affects software systems that rely on potrace for bitmap processing. Applications such as graphic design suites, document conversion tools, and image processing software that utilize this library become vulnerable to remote code execution when handling untrusted BMP inputs. The vulnerability's potential for unspecified impact reflects the complexity of heap corruption scenarios, where attackers might achieve different outcomes including privilege escalation, information disclosure, or complete system compromise depending on the execution environment. From an adversarial perspective, this vulnerability aligns with ATT&CK technique T1059.007, which involves executing malicious code through compromised software libraries, making it particularly dangerous in enterprise environments where such libraries might be widely deployed. The vulnerability's remote attack vector means that exploitation can occur without user interaction, making it a significant concern for web applications and services that process uploaded bitmap files.
Mitigation strategies for CVE-2016-8698 primarily involve upgrading to potrace version 1.13 or later, where the buffer overflow has been addressed through proper bounds checking and memory allocation validation. System administrators should implement strict input validation for all bitmap file processing operations, particularly in web-facing applications that accept user uploads. Additional defensive measures include deploying heap-based protection mechanisms such as stack canaries, address space layout randomization, and non-executable stack protections. Organizations should also consider implementing network segmentation and access controls to limit the potential impact of successful exploitation attempts. Regular security assessments of third-party libraries and dependencies are crucial for identifying similar vulnerabilities in other software components. The vulnerability serves as a reminder of the importance of maintaining up-to-date software libraries and implementing comprehensive security testing procedures that include fuzzing and memory safety analysis to prevent similar heap-based issues from occurring in other software components.