CVE-2015-6698 in Acrobat Reader
Summary
by MITRE
Heap-based buffer overflow in the AcroForm implementation in Adobe Reader and Acrobat 10.x before 10.1.16 and 11.x before 11.0.13, Acrobat and Acrobat Reader DC Classic before 2015.006.30094, and Acrobat and Acrobat Reader DC Continuous before 2015.009.20069 on Windows and OS X allows attackers to execute arbitrary code via unspecified vectors, a different vulnerability than CVE-2015-6696.
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Analysis
by VulDB Data Team • 06/21/2022
The vulnerability identified as CVE-2015-6698 represents a critical heap-based buffer overflow within Adobe Reader and Acrobat's AcroForm implementation across multiple product versions. This flaw exists in the handling of form data structures and specifically affects Adobe Reader versions 10.x before 10.1.16 and 11.x before 11.0.13, alongside Acrobat and Acrobat Reader DC Classic and Continuous versions prior to their respective patch releases. The vulnerability manifests on both Windows and macOS operating systems, making it particularly dangerous due to its broad platform scope. Unlike CVE-2015-6696 which addressed a different vector, this vulnerability operates through distinct attack paths that exploit memory corruption in the form processing subsystem.
The technical implementation of this vulnerability stems from inadequate bounds checking within the AcroForm parser component of Adobe's PDF processing engine. When processing maliciously crafted PDF documents containing specially constructed form fields, the application fails to properly validate input data lengths against allocated heap memory regions. This oversight allows attackers to write data beyond the intended buffer boundaries, potentially overwriting adjacent memory locations including function pointers, return addresses, or other critical program state information. The heap-based nature of the overflow means that memory corruption occurs in dynamically allocated regions rather than stack-based buffers, making exploitation more complex but potentially more reliable due to the predictable memory layout patterns.
From an operational perspective, this vulnerability presents a significant risk to enterprise environments where Adobe Reader remains widely deployed for document processing. Attackers can leverage this flaw by crafting malicious PDF files that, when opened by an affected version of Adobe Reader, trigger the buffer overflow condition. The successful exploitation results in arbitrary code execution with the privileges of the user running the application, potentially enabling full system compromise. The vulnerability's impact extends beyond individual user machines to entire organizational networks since PDF documents are commonly shared through email, file servers, and web portals. Security researchers have classified this as a high-severity issue due to its remote exploitability and the widespread use of Adobe Reader in corporate environments, making it a prime target for targeted attacks and mass exploitation campaigns.
Mitigation strategies for CVE-2015-6698 primarily focus on immediate patch deployment and administrative controls. Organizations should prioritize updating all affected Adobe Reader and Acrobat installations to their latest versions, specifically targeting the patches released for versions 10.1.16, 11.0.13, and the corresponding DC releases. Network administrators should implement PDF content filtering solutions that scan incoming documents for malicious patterns and consider disabling JavaScript execution in PDF readers where possible. The vulnerability aligns with ATT&CK technique T1203 (Exploitation for Client Execution) and CWE-121 (Stack-based Buffer Overflow) while also demonstrating characteristics of CWE-787 (Out-of-bounds Write) in its heap corruption implementation. Additional protective measures include user education regarding suspicious PDF attachments, implementation of sandboxing technologies, and deployment of endpoint protection solutions that can detect and block exploitation attempts. Regular security assessments should verify that all Adobe products within the organization have been properly updated and that no legacy versions remain in use, as the vulnerability's exploitation potential remains significant even in environments with limited internet connectivity.