CVE-2018-4907 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 TIFF processing in the XPS module. A successful attack can lead to sensitive data exposure.
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Analysis
by VulDB Data Team • 02/10/2023
The vulnerability identified as CVE-2018-4907 represents a classic buffer over-read flaw that affects multiple versions of Adobe Acrobat Reader across different release cycles. This security issue manifests within the TIFF processing functionality of the XPS module, which is responsible for handling XML Paper Specification documents that often contain embedded image data. The flaw occurs when the application processes TIFF formatted images within XPS documents, specifically during the memory allocation and data reading operations that occur when parsing these image files. The vulnerability is particularly concerning because it exists in a component that is frequently accessed when users open documents containing embedded images, making it a prime target for exploitation in real-world scenarios.
The technical root cause of this vulnerability stems from improper bounds checking during the processing of TIFF image data within the XPS module. When the application encounters a malformed or specially crafted TIFF file embedded within an XPS document, the buffer management logic fails to properly validate the boundaries of the data being read. This results in the application attempting to access memory locations beyond the allocated buffer space, which can lead to reading sensitive data that may have been previously stored in memory. The computation that triggers this behavior reads data past the end of the target buffer, creating a condition where adjacent memory contents are exposed to the application's processing logic. This type of vulnerability is categorized under CWE-125 as "Out-of-Bounds Read" and represents a fundamental flaw in memory safety practices that can potentially expose confidential information stored in adjacent memory regions.
The operational impact of CVE-2018-4907 extends beyond simple data exposure, as it can provide attackers with access to sensitive information that may include cryptographic keys, user credentials, or other confidential data that was previously stored in memory. The vulnerability is particularly dangerous in targeted attack scenarios where adversaries might craft malicious XPS documents containing specially constructed TIFF images designed to trigger the buffer over-read condition. Successful exploitation could lead to information disclosure that might be leveraged in subsequent attacks, potentially compromising user privacy and system security. The attack surface is broad since XPS documents are commonly shared and opened by users, making this vulnerability particularly effective for phishing campaigns or targeted attacks against specific organizations. This vulnerability aligns with ATT&CK technique T1059.007 for "Command and Scripting Interpreter: JavaScript' and T1566.001 for "Phishing: Spearphishing Attachment" as it can be delivered through malicious document attachments that exploit the buffer over-read condition when opened by vulnerable software.
Organizations and users should immediately apply the security patches provided by Adobe to address this vulnerability in all affected versions of Acrobat Reader. The recommended mitigation strategy involves updating to the latest versions of Adobe Acrobat Reader where the buffer over-read condition has been corrected through proper bounds checking implementations. Additionally, administrators should consider implementing document filtering policies that restrict the opening of XPS documents from untrusted sources and monitor for suspicious file attachments in email systems. Security awareness training for users should emphasize the importance of not opening suspicious documents, particularly those containing embedded images or complex formatting that might trigger such vulnerabilities. The vulnerability demonstrates the importance of proper memory management practices and highlights the need for regular security updates to protect against known exploitation techniques that can be readily weaponized by threat actors.