CVE-2018-4886 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 occurs in the image conversion engine when processing Enhanced Metafile Format (EMF) data related to handling of bitmap rectangles. A successful attack can lead to sensitive data exposure.
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Analysis
by VulDB Data Team • 07/23/2024
This vulnerability in Adobe Acrobat Reader represents a classic buffer overflow condition that manifests during image processing operations. The flaw exists within the image conversion engine's handling of Enhanced Metafile Format (EMF) data, specifically when processing bitmap rectangles. The vulnerability stems from improper bounds checking during memory allocation and data processing, allowing an attacker to manipulate memory access patterns that extend beyond allocated buffer boundaries. This type of vulnerability falls under the CWE-125 weakness category, which specifically addresses out-of-bounds read conditions that can lead to information disclosure and potential system compromise.
The technical implementation of this vulnerability exploits the image conversion engine's failure to properly validate input data dimensions and memory boundaries when processing EMF files containing bitmap rectangles. When the software attempts to read data beyond the intended buffer limits, it may access adjacent memory regions that could contain sensitive information such as cryptographic keys, user credentials, or system memory contents. The vulnerability is particularly dangerous because it occurs during routine document processing operations, making it difficult to distinguish between legitimate and malicious file processing activities. This aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as the vulnerability enables arbitrary code execution through carefully crafted EMF files that can be delivered via email attachments or malicious web content.
The operational impact of this vulnerability extends beyond simple information disclosure to potentially enable more sophisticated attacks including privilege escalation and system compromise. Attackers can craft malicious EMF files that trigger the buffer overflow condition when opened in vulnerable versions of Adobe Acrobat Reader, leading to exposure of sensitive data stored in adjacent memory locations. The vulnerability affects multiple product versions across different release cycles, indicating a persistent flaw in the image processing subsystem that was not adequately addressed through previous security updates. Organizations using affected versions of Adobe Acrobat Reader face significant risk exposure, as the vulnerability can be exploited through social engineering attacks targeting end users with malicious document attachments. The exploitation requires minimal user interaction beyond opening the malicious document, making it particularly dangerous in enterprise environments where document sharing is common.
Mitigation strategies should prioritize immediate patching of affected Adobe Acrobat Reader installations to the latest security updates provided by Adobe. Organizations should implement network-based protections including email filtering and web proxy restrictions that block potentially malicious EMF files from entering the enterprise network. Additionally, security teams should consider implementing application whitelisting policies that restrict execution of untrusted document processing software. The vulnerability demonstrates the importance of input validation and bounds checking in image processing libraries, which should be reinforced through security code reviews and static analysis tools. Regular security assessments of document processing applications and implementation of principle of least privilege access controls can help reduce the potential impact of similar vulnerabilities in the future. Organizations should also monitor for related vulnerabilities in similar software components and maintain updated threat intelligence feeds to detect potential exploitation attempts targeting this class of buffer overflow conditions.