CVE-2018-4951 in Acrobat Reader
Summary
by MITRE
Adobe Acrobat and Reader versions 2018.011.20038 and earlier, 2017.011.30079 and earlier, and 2015.006.30417 and earlier have an Out-of-bounds read vulnerability. Successful exploitation could lead to information disclosure.
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Analysis
by VulDB Data Team • 07/21/2024
Adobe Acrobat and Reader applications contain a critical out-of-bounds read vulnerability that affects multiple versions across different release cycles. This vulnerability resides in the handling of malformed PDF files and occurs when the software attempts to read memory locations beyond the allocated buffer boundaries. The flaw manifests during the processing of specially crafted PDF documents that contain malformed data structures, particularly in the way the applications parse and interpret certain object types within the document hierarchy. The vulnerability is classified as CWE-125 - Out-of-Bounds Read, which represents a fundamental memory safety issue where the application accesses memory locations that are outside the intended bounds of allocated memory regions. This type of vulnerability commonly arises from insufficient bounds checking during parsing operations and can lead to unpredictable behavior including information disclosure, application crashes, or potentially more severe consequences depending on the execution context.
The operational impact of this vulnerability extends beyond simple information disclosure, as it creates opportunities for attackers to extract sensitive data from the application's memory space. When exploited, the out-of-bounds read can potentially reveal memory contents including stack data, heap information, or other sensitive variables that might contain authentication tokens, user credentials, or internal application state information. The vulnerability affects multiple product versions including the 2018, 2017, and 2015 release series, indicating a persistent issue in the parsing logic that has remained unaddressed across several major releases. Attackers can leverage this vulnerability by crafting malicious PDF files that trigger the specific parsing path where the out-of-bounds read occurs, potentially leading to unauthorized access to sensitive information that should remain protected within the application's memory space. The vulnerability's exploitation requires the user to open a specially crafted PDF file, making it a client-side attack vector that relies on social engineering to achieve successful compromise.
From a threat modeling perspective, this vulnerability aligns with ATT&CK technique T1059.007 - Command and Scripting Interpreter: PowerShell, in that it represents a path for attackers to gain information that could be used for further exploitation, though it primarily functions as an information disclosure mechanism rather than a direct execution vector. The vulnerability's presence in widely used document processing software creates a significant risk profile, as it can be exploited in targeted attacks against individuals or organizations that regularly handle PDF documents. Security professionals should note that this vulnerability represents a classic example of how memory safety issues in complex parsing libraries can create persistent security risks, particularly in applications that process untrusted input from external sources. The vulnerability's exploitation potential increases when combined with other techniques that might be used to escalate privileges or achieve code execution, making it a critical concern for enterprise security teams managing Acrobat and Reader installations. Organizations should prioritize patching this vulnerability across all affected versions to prevent potential exploitation and maintain the integrity of their document processing environments. The issue demonstrates the importance of comprehensive memory safety testing and validation of parsing logic in security-critical applications, particularly those handling untrusted file formats that are commonly exchanged in business and personal communications.