CVE-2016-5688 in ImageMagick
Summary
by MITRE
The WPG parser in ImageMagick before 6.9.4-4 and 7.x before 7.0.1-5, when a memory limit is set, allows remote attackers to have unspecified impact via vectors related to the SetImageExtent return-value check, which trigger (1) a heap-based buffer overflow in the SetPixelIndex function or an invalid write operation in the (2) ScaleCharToQuantum or (3) SetPixelIndex functions.
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Analysis
by VulDB Data Team • 10/06/2022
The vulnerability CVE-2016-5688 represents a critical heap-based buffer overflow in ImageMagick's WPG parser that affects versions prior to 6.9.4-4 and 7.x prior to 7.0.1-5. This flaw exists within the memory management system where the SetImageExtent function fails to properly validate return values, creating opportunities for remote attackers to exploit memory corruption vulnerabilities. The issue specifically manifests when a memory limit is enforced during image processing operations, making it particularly dangerous in environments where untrusted image files are processed.
The technical exploitation of this vulnerability occurs through improper validation of the SetImageExtent return value within the WPG parser implementation. When processing maliciously crafted WPG files, the parser fails to check the return status of SetImageExtent, leading to heap-based buffer overflow conditions in the SetPixelIndex function. Additionally, the vulnerability can trigger invalid write operations in either the ScaleCharToQuantum or SetPixelIndex functions, depending on the specific attack vector employed. This represents a classic case of improper input validation and memory management error that aligns with CWE-121 heap-based buffer overflow and CWE-787 out-of-bounds write conditions.
The operational impact of this vulnerability extends beyond simple denial of service scenarios to potentially enable remote code execution in vulnerable environments. Attackers can leverage this flaw to manipulate heap memory layout, potentially leading to arbitrary code execution with the privileges of the ImageMagick process. The vulnerability is particularly concerning in web applications and services that process user-uploaded images, as it allows for remote exploitation without requiring authentication. The memory limit enforcement mechanism that triggers this vulnerability suggests that the flaw is specifically targeted at resource-constrained environments where memory allocation decisions are critical for system stability.
Security professionals should consider this vulnerability in the context of the ATT&CK framework, particularly under the techniques related to exploitation of memory corruption vulnerabilities. The vulnerability demonstrates how improper error handling in image processing libraries can create persistent security risks in web applications and content management systems. Organizations should prioritize immediate patching of affected ImageMagick installations and implement additional safeguards such as image validation, sandboxing, and strict input filtering. The remediation process should include not only updating to patched versions but also reviewing system configurations to ensure proper memory limit enforcement and monitoring for potential exploitation attempts. This vulnerability highlights the importance of thorough input validation and proper error handling in multimedia processing libraries that are widely deployed across internet-facing applications.