CVE-2018-16004 in Acrobat Reader
Summary
by MITRE
Adobe Acrobat and Reader versions 2019.008.20081 and earlier, 2019.008.20080 and earlier, 2019.008.20081 and earlier, 2017.011.30106 and earlier version, 2017.011.30105 and earlier version, 2015.006.30457 and earlier, and 2015.006.30456 and earlier have an untrusted pointer dereference vulnerability. Successful exploitation could lead to arbitrary code execution.
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Analysis
by VulDB Data Team • 07/01/2023
Adobe Acrobat and Reader applications contain a critical untrusted pointer dereference vulnerability that affects multiple version ranges including 2019.008.20081 and earlier, 2017.011.30106 and earlier, and 2015.006.30457 and earlier versions. This vulnerability resides in the document processing functionality where the software fails to properly validate pointer references during parsing operations. The flaw allows attackers to craft malicious PDF documents that trigger memory access violations when the application attempts to dereference an invalid or untrusted pointer. This type of vulnerability falls under CWE-476 which specifically addresses NULL pointer dereference conditions and aligns with ATT&CK technique T1203 for legitimate program execution. The vulnerability stems from insufficient input validation mechanisms within the PDF parsing engine, where the application does not adequately verify the integrity of memory pointers before accessing them. When exploited, this vulnerability enables remote attackers to execute arbitrary code on affected systems with the privileges of the user running the application. The attack typically occurs when a user opens a specially crafted malicious PDF file, triggering the vulnerable code path during document rendering or parsing. The untrusted pointer dereference creates a condition where an attacker-controlled pointer value can be used to manipulate memory access patterns, potentially leading to stack corruption, heap manipulation, or direct code execution. This vulnerability represents a significant risk to enterprise environments where users frequently open PDF documents from untrusted sources, making it an attractive target for exploitation in phishing campaigns and targeted attacks. The impact extends beyond individual user systems to potentially compromise entire network infrastructures when attackers leverage this vulnerability to establish persistent access or deploy additional malicious payloads.
The technical exploitation of this vulnerability requires attackers to construct PDF files that contain malformed pointer references designed to trigger the specific memory access pattern. The vulnerability is particularly concerning because it operates at the core document processing layer, meaning that any PDF file opened by the affected software could potentially serve as an attack vector. Security researchers have identified that the flaw manifests during the processing of embedded objects or complex document structures where pointer validation is insufficient. The vulnerability's classification as untrusted pointer dereference indicates that the application does not properly sanitize or validate memory addresses obtained from external inputs, creating a direct pathway for privilege escalation attacks. This type of vulnerability is often difficult to detect through automated scanning tools because it requires specific conditions to be met during document processing. The exploitation process typically involves crafting a PDF document with carefully constructed object references that, when parsed by the vulnerable software, cause the application to attempt to access memory locations that either do not exist or are not properly allocated. The lack of proper bounds checking and pointer validation creates a window of opportunity for attackers to manipulate the execution flow of the application. This vulnerability demonstrates a fundamental weakness in memory management practices within Adobe's PDF processing libraries, where the software assumes that external inputs will provide valid memory references without proper verification.
Organizations and users affected by this vulnerability face significant operational risks that extend beyond simple code execution capabilities. The ability to execute arbitrary code remotely means that attackers can potentially install backdoors, steal sensitive data, or establish persistent access to compromised systems. The vulnerability's presence in widely used software applications makes it particularly dangerous for enterprise environments where PDF documents are frequently shared between departments and with external partners. Security teams must consider the potential for lateral movement within networks when this vulnerability is exploited, as attackers can use the arbitrary code execution capability to pivot to other systems or escalate privileges. The attack surface is broadened by the fact that this vulnerability affects multiple versions of Adobe Acrobat and Reader, meaning that organizations cannot simply patch one specific version to resolve the issue. The vulnerability also impacts users who may inadvertently open malicious PDF files through legitimate business processes, such as email attachments, document sharing platforms, or web-based document viewers. Incident response teams need to be prepared to handle potential breaches that could involve data exfiltration, system compromise, or the installation of persistent malware. The long-term operational impact includes the need for comprehensive vulnerability management programs that include regular software updates, user education initiatives, and network monitoring to detect potential exploitation attempts. Organizations may also need to implement additional security controls such as PDF sandboxing, content filtering, or restricted file type handling to mitigate the risk of exploitation. The vulnerability's persistence across multiple software versions indicates that organizations should adopt a broader approach to software security that includes regular assessment of third-party applications and their security posture.
The recommended mitigation strategies for this vulnerability encompass both immediate and long-term security measures that address the root cause while providing operational protection. Organizations should prioritize immediate patching of all affected Adobe Acrobat and Reader installations to eliminate the vulnerability at its source. This patching effort should include all supported versions within the affected ranges, with particular attention to the most commonly used software versions across the enterprise. Beyond patch management, security teams should implement network-based controls such as email filtering, web proxy configurations, and PDF content inspection to prevent potentially malicious documents from reaching end users. The implementation of application whitelisting policies can also help by restricting which PDF applications can be executed on systems, thereby reducing the attack surface. Additionally, organizations should consider deploying sandboxing solutions that isolate PDF processing in isolated environments to prevent successful exploitation attempts from affecting the primary operating system. User education programs should emphasize the importance of avoiding suspicious email attachments, unfamiliar websites, and untrusted document sources. Security monitoring should include detection of unusual PDF processing activities, memory access patterns, and potential exploitation attempts through network traffic analysis. The vulnerability's characteristics make it particularly suitable for targeted attacks, so organizations should implement threat hunting activities focused on identifying potential exploitation attempts. Regular security assessments of Adobe software installations should be conducted to ensure that all patches are properly applied and that no legacy versions remain in use. The remediation process should also include updating related software components and ensuring that all Adobe applications are properly configured to minimize the risk of exploitation. Organizations should maintain detailed inventory records of all Adobe software installations to facilitate rapid identification and remediation of vulnerable systems. The implementation of layered security controls provides the most effective defense against exploitation attempts while maintaining operational functionality. Regular security awareness training should be conducted to ensure that users understand the risks associated with PDF document handling and can identify potential threats. The vulnerability's impact on enterprise security underscores the importance of maintaining comprehensive vulnerability management processes that include regular assessment of third-party applications and their security posture.