CVE-2018-4906 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. This vulnerability occurs as a result of computation that reads data that is past the end of the target buffer; the computation is part of the image conversion module that handles Enhanced Metafile Format Plus (EMF+) data related to graphic object image attributes. A successful attack can lead to sensitive data exposure.
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Analysis
by VulDB Data Team • 02/10/2023
The vulnerability identified as CVE-2018-4906 represents a critical buffer overread flaw in Adobe Acrobat Reader affecting multiple version ranges including 2018.009.20050 and earlier, 2017.011.30070 and earlier, and 2015.006.30394 and earlier versions. This security weakness resides within the image conversion module responsible for processing Enhanced Metafile Format Plus (EMF+) data structures that contain graphic object image attributes. The flaw manifests when the application performs computations that access memory locations beyond the allocated buffer boundaries during EMF+ data processing operations. This type of vulnerability falls under the category of CWE-125, which specifically addresses out-of-bounds read conditions in software implementations. The issue demonstrates characteristics consistent with memory safety vulnerabilities that are commonly exploited in cyber attacks targeting document readers and office applications.
The technical exploitation of this vulnerability occurs when Adobe Acrobat Reader encounters specially crafted EMF+ formatted graphics within PDF documents. During the conversion process of these graphic elements, the application's image handling code executes calculations that reference memory addresses extending beyond the intended buffer limits. This overread condition allows attackers to potentially access adjacent memory regions containing sensitive data such as passwords, encryption keys, or other confidential information stored in the application's memory space. The attack vector typically involves tricking users into opening maliciously crafted PDF files containing crafted EMF+ graphics that trigger the vulnerable code path. From an operational security perspective, this vulnerability represents a significant risk to organizations as it can be exploited through social engineering campaigns targeting end users with malicious attachments or documents.
The impact of CVE-2018-4906 extends beyond simple data exposure, as it can potentially enable more sophisticated attack scenarios within the broader adversary tactics framework. According to ATT&CK framework categorization, this vulnerability could be leveraged as part of initial access or privilege escalation techniques, particularly when combined with other exploitation methods. The vulnerability's presence in multiple versions of Adobe Acrobat Reader indicates a widespread exposure across different organizational environments, making it an attractive target for threat actors seeking to compromise large user bases. Security researchers have noted that such buffer overread conditions often provide attackers with information that can be used to further refine exploitation techniques or bypass security controls. The vulnerability's classification as a memory safety issue aligns with common attack patterns observed in the cybersecurity landscape where adversaries target document processing applications due to their frequent use in enterprise environments.
Organizations should implement immediate mitigation strategies including prompt patching of affected Adobe Acrobat Reader versions to address this vulnerability. The recommended approach involves deploying the latest security updates from Adobe which contain fixes for the buffer overread condition in the EMF+ processing module. System administrators should also consider implementing additional protective measures such as email filtering solutions that can identify and block malicious PDF attachments containing crafted EMF+ graphics. Network-based intrusion detection systems should be configured to monitor for suspicious document processing activities that might indicate exploitation attempts. From a defensive standpoint, organizations should conduct comprehensive vulnerability assessments to identify all systems running affected Adobe Reader versions and prioritize remediation efforts accordingly. The vulnerability's nature as a buffer overread condition makes it particularly susceptible to exploitation through targeted attacks, emphasizing the importance of timely patch management and proactive security monitoring.