CVE-2018-4915 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. The vulnerability is caused by the computation that writes data past the end of the intended buffer; the computation is part of the JavaScript API related to color conversion. An attacker can potentially leverage the vulnerability to corrupt sensitive data or execute arbitrary code.
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Analysis
by VulDB Data Team • 07/22/2024
This vulnerability exists in Adobe Acrobat Reader across multiple version lines including 2018.009.20050 and earlier, 2017.011.30070 and earlier, and 2015.006.30394 and earlier versions. The issue stems from improper buffer boundary checking within the JavaScript API implementation specifically related to color conversion operations. The flaw manifests when the application processes color data through JavaScript functions that fail to validate buffer limits during data manipulation. This type of vulnerability falls under the category of buffer overflow conditions as defined by CWE-121, where insufficient boundary checks allow data to be written beyond the allocated memory space. The vulnerability is particularly concerning because it occurs within the JavaScript execution environment of the PDF reader, which is commonly used for document processing and can be easily triggered through malicious PDF files.
The technical exploitation of this vulnerability occurs when an attacker crafts a malicious PDF document containing specially crafted JavaScript code that invokes color conversion functions. The JavaScript API implementation fails to properly validate input parameters or buffer sizes during color space conversions, leading to memory corruption when data is written past the intended buffer boundaries. This memory corruption can result in unpredictable behavior including application crashes, data corruption, or more critically, arbitrary code execution. The vulnerability represents a classic buffer overflow scenario where the computation logic does not account for proper bounds checking, allowing attackers to overwrite adjacent memory locations. The attack vector is primarily through malicious PDF files delivered via email, web downloads, or other means of document distribution, making it particularly dangerous in enterprise environments where PDF documents are frequently opened and processed.
The operational impact of this vulnerability extends beyond simple application instability to potential system compromise and data breaches. When successfully exploited, the buffer overflow can allow attackers to execute arbitrary code with the privileges of the Acrobat Reader application, potentially leading to full system compromise if the application runs with elevated privileges. The vulnerability affects a wide range of Acrobat Reader versions, making it particularly impactful across different deployment scenarios and organizational environments. Organizations that regularly process PDF documents, especially those containing JavaScript functionality, face significant risk from this vulnerability. The attack surface is broad as PDF documents are commonly used in business communications, legal proceedings, and various other professional contexts where document processing is routine. This vulnerability also aligns with ATT&CK technique T1204.002, where adversaries leverage software execution via legitimate user interfaces to establish persistent access or escalate privileges.
Mitigation strategies should focus on immediate patching of affected versions to address the buffer overflow condition in the JavaScript color conversion API. Organizations must ensure all Acrobat Reader installations are updated to versions that contain the security fixes, with particular attention to the specific version ranges mentioned in the vulnerability description. Additional defensive measures include implementing PDF document scanning and filtering at network boundaries, disabling JavaScript execution in Acrobat Reader when possible, and using sandboxing techniques to isolate PDF processing operations. The vulnerability highlights the importance of proper input validation and boundary checking in application code, particularly in environments where third-party libraries and scripting engines are integrated. Security monitoring should focus on unusual PDF processing patterns and potential exploitation attempts through malicious document delivery methods, as the vulnerability can be leveraged for initial access or privilege escalation within targeted environments.