CVE-2016-8699 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-2016-8700, CVE-2016-8701, CVE-2016-8702, and CVE-2016-8703.
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Analysis
by VulDB Data Team • 08/08/2020
The heap-based buffer overflow vulnerability identified as CVE-2016-8699 affects the potrace library version 1.12 and earlier, specifically within the bm_readbody_bmp function located in bitmap_io.c. This vulnerability represents a critical security flaw that enables remote attackers to exploit memory corruption through carefully crafted BMP image files. The issue stems from inadequate input validation and bounds checking during the processing of bitmap image data, creating an opportunity for malicious actors to manipulate heap memory allocation and potentially execute arbitrary code. The vulnerability operates independently from other related issues such as CVE-2016-8698 through CVE-2016-8703, indicating a distinct code path and attack surface within the potrace library's bitmap handling capabilities.
The technical exploitation of this buffer overflow occurs when the bm_readbody_bmp function processes malformed BMP image data without proper validation of buffer sizes or memory boundaries. When a maliciously crafted BMP file is processed, the function fails to adequately check the dimensions or data length of the image header fields, leading to a situation where more data is written to heap memory than allocated. This heap-based overflow creates opportunities for attackers to overwrite adjacent memory locations, potentially corrupting program state or executing malicious code. The vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions where insufficient bounds checking allows attackers to write beyond allocated buffer boundaries. The flaw particularly affects the memory management operations within the potrace library's image processing pipeline, where the function attempts to read and parse bitmap image data structures.
The operational impact of this vulnerability extends across multiple attack vectors and system environments where potrace is utilized for vector graphics conversion or image processing tasks. Remote attackers can leverage this vulnerability through web applications, document processing systems, or any service that accepts and processes BMP image files without proper sanitization. The unspecified impact mentioned in the CVE description suggests that exploitation could lead to various outcomes including denial of service, arbitrary code execution, or information disclosure depending on the specific memory corruption patterns and system configurations. Attackers may exploit this vulnerability by uploading crafted BMP files to systems that use potrace for image conversion or by manipulating image processing workflows in applications that depend on this library. The vulnerability's remote exploitability makes it particularly dangerous in web-facing applications or services that process user-uploaded content, as demonstrated by the ATT&CK technique T1203 which covers exploitation of remote services through malformed input.
Mitigation strategies for CVE-2016-8699 should focus on immediate patching of affected potrace installations to version 1.13 or later where the heap overflow has been addressed through proper bounds checking and input validation. Organizations should implement comprehensive input sanitization measures for all image processing workflows, including the validation of BMP file headers and dimensions before processing. Network segmentation and access controls should be strengthened to limit exposure of systems that process image files, particularly those using vulnerable versions of potrace. The implementation of memory protection mechanisms such as stack canaries, address space layout randomization, and data execution prevention can provide additional defense-in-depth measures against exploitation attempts. Security monitoring should be enhanced to detect unusual image processing patterns or attempts to upload suspicious file types, with regular vulnerability scanning to identify systems running outdated versions of the potrace library. System administrators should also consider implementing automated patch management processes to ensure timely updates of security patches across all affected systems and applications that depend on this vulnerable library.