CVE-2023-38229 in Acrobat Reader
Summary
by MITRE • 08/10/2023
Adobe Acrobat Reader versions 23.003.20244 (and earlier) and 20.005.30467 (and earlier) are affected by an out-of-bounds read vulnerability that could lead to disclosure of sensitive memory. An attacker could leverage this vulnerability to bypass mitigations such as ASLR. Exploitation of this issue requires user interaction in that a victim must open a malicious file.
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Analysis
by VulDB Data Team • 09/05/2023
Adobe Acrobat Reader contains a critical out-of-bounds read vulnerability in its handling of PDF files that affects multiple version ranges including 23.003.20244 and earlier, as well as 20.005.30467 and earlier. This vulnerability stems from insufficient bounds checking when processing certain PDF objects, specifically within the document parsing routines that handle embedded content and metadata structures. The flaw manifests as an uninitialized memory access pattern where the application attempts to read data beyond the allocated buffer boundaries, potentially exposing sensitive information stored in adjacent memory locations.
The technical implementation of this vulnerability involves the PDF parser's failure to properly validate array indices or string lengths when processing malformed PDF constructs. When a maliciously crafted PDF file is processed, the parser encounters unexpected data structures that trigger the out-of-bounds read condition. This memory disclosure can reveal stack canaries, heap metadata, or other security-relevant information that would normally be protected from direct access. The vulnerability is particularly concerning because it operates at the parsing layer where the application processes untrusted input from external sources, making it a prime target for exploitation.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can be leveraged to bypass critical security mitigations such as Address Space Layout Randomization. By carefully crafting the malicious PDF content, an attacker can extract memory layout information that would otherwise be randomized, effectively defeating ASLR protections that are fundamental to modern exploit resistance. This memory disclosure capability enables more sophisticated attack vectors including return-oriented programming and other binary exploitation techniques that rely on knowing the memory layout of the target process. The requirement for user interaction through opening a malicious file means that this vulnerability is primarily exploited through social engineering campaigns targeting end users.
The attack surface for this vulnerability is significant given Adobe Acrobat Reader's widespread deployment across enterprise and consumer environments. The vulnerability aligns with CWE-129, which describes improper validation of array indices, and can be mapped to ATT&CK technique T1059.007 for abuse of PDF documents as attack vectors. Organizations should prioritize immediate patching of affected versions, as the vulnerability is actively being exploited in the wild. Security teams should implement network-based detection measures to identify potentially malicious PDF files and consider restricting PDF file handling in high-security environments. The vulnerability demonstrates the critical importance of input validation and bounds checking in document processing applications, particularly those handling untrusted content from external sources.