CVE-2018-17607 in PhantomPDF
Summary
by MITRE
Foxit PhantomPDF and Reader before 9.3 allow remote attackers to execute arbitrary code or cause a denial of service (use-after-free) because properties of Annotation objects are mishandled. This relates to one of five distinct types of Annotation objects.
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Analysis
by VulDB Data Team • 03/27/2020
CVE-2018-17607 represents a critical use-after-free vulnerability affecting Foxit PhantomPDF and Reader versions prior to 9.3. This flaw resides in the improper handling of Annotation object properties within the PDF processing engine, creating a remote code execution vector that can be exploited by malicious actors. The vulnerability specifically impacts one of five distinct Annotation object types, indicating a targeted weakness in the software's object management system. The use-after-free condition occurs when memory is accessed after it has been freed, allowing attackers to manipulate the freed memory location for arbitrary code execution or system instability. This type of vulnerability falls under CWE-416, which specifically addresses use-after-free conditions in software applications. The attack vector is particularly concerning as it enables remote exploitation without requiring user interaction, making it a significant threat to organizations that rely on PDF processing software for document handling and sharing.
The technical implementation of this vulnerability stems from inadequate memory management within the Annotation processing subsystem. When Annotation objects are created and subsequently destroyed, the software fails to properly invalidate references to the freed memory locations. This allows an attacker to craft malicious PDF documents containing specially constructed Annotation objects that trigger the use-after-free condition during normal PDF rendering operations. The vulnerability's impact extends beyond simple code execution to include potential denial of service scenarios, where system resources can be exhausted or application stability can be compromised through repeated exploitation attempts. The flaw demonstrates poor adherence to secure coding practices and highlights the importance of proper memory lifecycle management in complex software applications. Security researchers have identified this as a high-risk vulnerability that could be leveraged in targeted attacks against unsuspecting users who open malicious PDF documents.
Organizations utilizing affected versions of Foxit PhantomPDF and Reader face significant operational risks from this vulnerability. The remote exploitation capability means that attackers can compromise systems simply by sending malicious PDF files via email or hosting them on compromised websites. This vulnerability can be particularly dangerous in enterprise environments where PDF documents are frequently shared between departments and external partners. The potential for arbitrary code execution creates opportunities for attackers to establish persistent access, escalate privileges, or deploy additional malware payloads. System administrators must consider the broader implications of this vulnerability on their network security posture, as successful exploitation could lead to data breaches, system compromise, or unauthorized access to sensitive information. The vulnerability's classification as a remote code execution threat requires immediate attention and remediation efforts to prevent potential exploitation by threat actors.
Mitigation strategies for CVE-2018-17607 should prioritize immediate software updates to Foxit PhantomPDF and Reader 9.3 or later versions, which contain the necessary patches to address the use-after-free condition. Organizations should implement network-based controls such as PDF file filtering and sandboxing mechanisms to prevent potentially malicious documents from reaching end users. Security teams should conduct comprehensive vulnerability assessments to identify all systems running affected software versions and prioritize patching efforts accordingly. Additional protective measures include implementing email filtering solutions that scan for suspicious PDF attachments and establishing user awareness programs to educate staff about the risks of opening untrusted PDF documents. The vulnerability's relationship to ATT&CK technique T1204.002 demonstrates how this flaw could be used in conjunction with other attack vectors to establish persistent access or escalate privileges within compromised environments. Regular security monitoring and incident response procedures should be enhanced to detect potential exploitation attempts and respond rapidly to any signs of compromise. Organizations should also consider implementing zero-trust network architectures that limit the potential impact of successful exploitation attempts by restricting lateral movement and access privileges.