CVE-2018-4881 in Acrobat Reader
Summary
by MITRE
An issue was discovered in Adobe Acrobat Reader 2018.009.20050 and earlier versions, 2017.011.30070 and earlier versions, 2015.006.30394 and earlier versions. This vulnerability occurs as a result of computation that reads data that is past the end of the target buffer; the computation is part of the image conversion module that reads bitmap image file (BMP) data. A successful attack can lead to sensitive data exposure.
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Analysis
by VulDB Data Team • 07/22/2024
This vulnerability exists in Adobe Acrobat Reader across multiple versions including 2018.009.20050 and earlier, 2017.011.30070 and earlier, and 2015.006.30394 and earlier. The flaw manifests within the image conversion module responsible for processing bitmap image files with the bmp file extension. The underlying issue stems from improper bounds checking during data processing where the application attempts to read memory locations beyond the allocated buffer boundaries. This type of vulnerability falls under the category of buffer over-read conditions as classified by CWE-126, which specifically addresses situations where a program reads data past the end of a buffer. The vulnerability occurs when the BMP image processing component performs computations that access memory locations beyond the intended data boundaries, creating potential exposure points for sensitive information.
The operational impact of this vulnerability extends beyond simple data corruption or application crashes. When exploited, the buffer over-read condition can result in information disclosure, where adjacent memory contents may be exposed to unauthorized access. This represents a significant security risk as attackers could potentially extract sensitive data from memory regions that contain credentials, encryption keys, or other confidential information. The vulnerability demonstrates a classic example of how seemingly benign file processing operations can become attack vectors when proper input validation and memory boundary checks are absent. This flaw aligns with ATT&CK technique T1059.007 which covers the use of remote code execution through file processing vulnerabilities, though the specific impact here is data exposure rather than code execution.
The technical implementation of this vulnerability involves the image conversion module's handling of BMP file structures where the parsing logic fails to properly validate the size parameters of the bitmap data before attempting to read from memory. This type of error commonly occurs in legacy code where buffer management was not adequately implemented or where assumptions were made about input data size and format. The attack vector requires an attacker to craft a malicious BMP file that triggers the buffer over-read condition during normal document rendering operations. Security practitioners should note that this vulnerability represents a persistent issue in document processing applications where image handling components are not properly secured against malformed input data. The vulnerability underscores the importance of implementing robust input validation and memory safety mechanisms, particularly in applications that process untrusted file formats as recommended by industry best practices for secure coding and application hardening.
Mitigation strategies should focus on immediate patching of affected Adobe Acrobat Reader versions to address the buffer over-read condition in the BMP image processing module. Organizations should also implement network segmentation and file validation controls to prevent automatic processing of untrusted BMP files. Additionally, regular security assessments of document processing components should be conducted to identify similar buffer handling vulnerabilities. The remediation approach should include comprehensive testing of image processing modules to ensure proper bounds checking and memory access validation. System administrators should consider implementing application whitelisting policies that restrict the execution of potentially vulnerable software versions until proper patches are deployed. This vulnerability highlights the critical need for continuous security monitoring and proactive vulnerability management in enterprise environments where document processing applications remain widely used.