CVE-2021-27807 is a medium-severity vulnerability affecting Apache PDFBox. This vulnerability allows a carefully crafted PDF file to trigger an infinite loop while loading the file. It impacts Apache PDFBox version 2.0.22 and prior versions in the 2.0.x series.
The vulnerability has a CVSS score of 5.5, indicating a medium severity level. The risk to organizations includes potential denial of service due to high availability impact. As such, organizations should address this vulnerability in their priority patch cycle.
Currently, there is no public exploit confirmed for this vulnerability, and it is not listed in the Known Exploited Vulnerabilities (KEV) catalog. However, the presence of this vulnerability remains a concern for system availability.
Organizations should prioritize patching immediately to mitigate potential disruptions caused by this vulnerability.
Mitigation strategies should include immediate application of patches along with regular security assessments.
In the context of threat intelligence, monitoring for any anomalies in PDF file handling can also provide an additional layer of defense.
Overall, CVE-2021-27807 represents a significant risk that organizations must address promptly.
Vulnerability Details
The official CVE description states that this vulnerability allows a carefully crafted PDF file to trigger an infinite loop while loading the file. The affected product is Apache PDFBox version 2.0.22 and prior 2.0.x versions. The vulnerability is classified under CWE-834.
The vulnerability has a CVSS 3.1 score of 5.5, indicating a medium severity level. This score reflects the potential for a denial of service condition due to high availability impact while confidentiality and integrity impacts are negligible.
Technical Analysis
The root cause of this vulnerability stems from improper handling of specially crafted PDF files by the Apache PDFBox library, which leads to an infinite loop during the file loading process.
The attack vector for this vulnerability is local, meaning that an attacker would need access to the system where the PDF file is processed. The attack complexity is low, requiring no special privileges, but it does require user interaction to open the malicious PDF file.
In terms of impact, the vulnerability poses a high risk to availability, as successful exploitation can lead to system crashes or unresponsiveness.
Risk & Impact Analysis
Risk to organizations includes potential denial of service, which can disrupt operations significantly. The blast radius is particularly concerning for organizations relying on PDF processing as part of their workflows.
Organizations should be aware of the implications of this vulnerability, especially those in sectors that frequently handle PDF documents. The urgency for remediation is classified as high due to the medium CVSS score and the potential availability impact.
Given the low exploitability score and the absence of confirmed public exploits, organizations should still address this vulnerability in their priority patch cycle.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The vulnerable versions of Apache PDFBox range from 2.0.0 to 2.0.22. Organizations running these versions should prioritize their upgrade to the latest patched version.
Mitigation & Remediation
To mitigate the risks associated with CVE-2021-27807, organizations should apply the latest patches provided by Apache. The recommended action is to upgrade to a version of Apache PDFBox that is higher than 2.0.22.
In cases where immediate patching is not feasible, organizations should consider implementing workarounds such as restricting user access to PDF file processing and monitoring for any abnormal behavior in file handling.
Regular security assessments and configuration hardening should be part of the routine maintenance to reduce the attack surface associated with PDF processing.
Detection Guidance
Organizations should monitor their systems for any signs of abnormal behavior when loading PDF files. This includes checking logs for infinite loops or crashes during PDF processing.
Behavioral anomalies should be flagged for further investigation, and network signatures for known malicious PDF files should be implemented to enhance detection capabilities.
AppSecure Threat Intelligence Insight
CVE-2021-27807 highlights significant risks associated with improper file handling in PDF processing libraries. This vulnerability serves as a reminder for organizations to maintain strict controls over user interactions with file uploads.
By understanding the implications of this vulnerability, security teams can better prepare for similar types of risks that may arise from new functionalities or third-party libraries.
Organizations are encouraged to stay informed about evolving vulnerabilities and to integrate threat intelligence into their security practices, ensuring they remain proactive against potential threats.
For further information on securing your applications, organizations may consider reviewing our guide on penetration testing methodology, which outlines best practices for identifying and mitigating vulnerabilities.
Known Exploitation Timeline
This section is not applicable as there is no KEV data available for this CVE.
EPSS Risk Context
The EPSS score for CVE-2021-27807 is 0.00492, placing it in the 65.72 percentile, indicating a low probability of exploitation in the wild.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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