CVE-2018-4891 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 XPS module that handles TIFF data. A successful attack can lead to sensitive data exposure.
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Analysis
by VulDB Data Team • 02/10/2023
CVE-2018-4891 represents a classic buffer over-read vulnerability affecting Adobe Acrobat Reader across multiple version lines including 2018.009.20050 and earlier, 2017.011.30070 and earlier, and 2015.006.30394 and earlier. This flaw exists within the XPS module responsible for processing TIFF data files, where improper boundary checking allows the application to read memory locations beyond the allocated buffer space. The vulnerability manifests when the application processes malformed or specially crafted TIFF files that trigger the over-read condition during data parsing operations. This type of issue falls under CWE-125, which specifically addresses out-of-bounds read vulnerabilities where programs access memory beyond the intended buffer boundaries.
The technical exploitation of this vulnerability occurs when Adobe Acrobat Reader attempts to parse TIFF image data within XPS documents, leading to unauthorized memory access patterns that can expose sensitive information stored in adjacent memory locations. The attack vector typically involves tricking a user into opening a maliciously crafted XPS file containing malformed TIFF data that triggers the buffer over-read condition. This vulnerability operates at the application layer and requires user interaction to be successfully exploited, making it a prime candidate for social engineering attacks within targeted campaigns. The security implications extend beyond simple information disclosure, as the leaked memory contents may contain cryptographic keys, user credentials, or other sensitive data that could be leveraged for further exploitation.
From an operational impact perspective, this vulnerability poses significant risks to enterprise environments where Adobe Acrobat Reader remains widely deployed for document processing. The vulnerability can result in data leakage from memory segments that may contain session tokens, temporary passwords, or other confidential information that applications store in nearby memory locations. The exposure of sensitive data through buffer over-reads can lead to credential theft, privilege escalation, or information disclosure attacks that compromise the confidentiality of organizational data. Organizations running affected versions of Adobe Acrobat Reader face potential exposure to attackers who can craft malicious documents to exploit this condition, potentially leading to unauthorized access to sensitive corporate or personal information.
The mitigation strategy for CVE-2018-4891 primarily involves immediate patching of Adobe Acrobat Reader installations to versions that address the buffer over-read condition in the XPS TIFF processing module. Organizations should implement strict document filtering policies that prevent the automatic opening of XPS or TIFF files from untrusted sources, particularly in high-security environments. Network-based protections can include implementing content filtering solutions that scan document attachments for known malicious patterns and implementing sandboxing technologies to isolate document processing operations. Additionally, security awareness training should emphasize the dangers of opening unexpected document attachments and the importance of verifying document sources before processing. The vulnerability demonstrates the importance of proper input validation and boundary checking in multimedia processing modules, aligning with ATT&CK technique T1059.007 for execution through macro and script-based attacks that leverage similar memory corruption vulnerabilities.