CVE-2018-4899 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 initial XPS page processing. A successful attack can lead to sensitive data exposure.
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Analysis
by VulDB Data Team • 07/22/2024
This vulnerability in Adobe Acrobat Reader represents a classic buffer overread flaw that occurs during XPS document processing, specifically during the initial page rendering phase. The issue manifests when the application performs computations that attempt to read data beyond the boundaries of allocated memory buffers, creating a condition where adjacent memory contents become accessible to the processing routine. The vulnerability affects multiple versions of Adobe Acrobat Reader across different release cycles, indicating a persistent flaw in the XPS parsing implementation that was not adequately addressed through previous security updates. This type of vulnerability falls under the category of memory safety issues commonly classified as CWE-125: "Out-of-bounds Read" within the CWE database, which represents one of the most prevalent categories of software vulnerabilities affecting enterprise applications.
The technical exploitation of this vulnerability occurs during the processing of XPS (XML Paper Specification) documents, which are used for document rendering and printing in various Microsoft and Adobe applications. When an attacker crafts a malicious XPS document containing specially constructed data, the Acrobat Reader application attempts to parse and render the document, triggering the buffer overread condition during the initial page processing phase. The computational logic responsible for handling XPS page data structures fails to properly validate buffer boundaries before accessing memory locations beyond the intended data set. This overread operation can potentially expose sensitive information stored in adjacent memory regions, including but not limited to application state data, user credentials, cryptographic keys, or other confidential information that may reside in the memory space adjacent to the targeted buffer.
The operational impact of this vulnerability extends beyond simple data exposure, as it represents a potential pathway for more sophisticated attacks within the context of targeted exploitation. An attacker who successfully triggers this vulnerability could potentially extract sensitive information from the application's memory space, which might include session tokens, user authentication data, or other confidential information that could be leveraged for further compromise. The vulnerability is particularly concerning in enterprise environments where Adobe Acrobat Reader is widely deployed, as it could enable attackers to gain access to sensitive documents and information that would otherwise be protected by standard security controls. This flaw creates a potential attack surface that aligns with techniques described in the ATT&CK framework under the T1059.007 sub-technique for "Command and Scripting Interpreter: Visual Basic' and T1068 for 'Exploitation for Privilege Escalation' when combined with other exploitation vectors.
Mitigation strategies for this vulnerability should focus on immediate version updates to the latest Adobe Acrobat Reader releases that contain patches addressing the buffer overread condition. Organizations should implement comprehensive patch management procedures to ensure all instances of the vulnerable software are updated across their networks. Additional defensive measures include deploying application whitelisting solutions that restrict execution of untrusted XPS documents, implementing network-based intrusion detection systems to monitor for suspicious document processing activities, and establishing strict document handling policies that require validation of all incoming documents before processing. Security teams should also consider implementing memory protection mechanisms such as data execution prevention and address space layout randomization to reduce the effectiveness of potential exploitation attempts. The vulnerability highlights the importance of robust input validation and memory boundary checking in document processing applications, particularly those handling complex markup formats like XPS that involve extensive parsing and rendering operations.