CVE-2009-1100 in JRE
Summary
by MITRE
Multiple unspecified vulnerabilities in Java SE Development Kit (JDK) and Java Runtime Environment (JRE) 5.0 Update 17 and earlier, and 6 Update 12 and earlier, allow remote attackers to cause a denial of service (disk consumption) via vectors related to temporary font files and (1) "limits on Font creation," aka CR 6522586, and (2) another unspecified vector, aka CR 6632886.
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Analysis
by VulDB Data Team • 08/09/2021
The vulnerability described in CVE-2009-1100 represents a significant denial of service weakness affecting Java SE Development Kit and Runtime Environment versions through specific update releases. This flaw manifests through improper handling of temporary font files during font creation processes, creating conditions where malicious actors can exploit the system's resource management mechanisms to consume excessive disk space. The vulnerability specifically impacts Java 5.0 Update 17 and earlier versions, as well as Java 6 Update 12 and earlier releases, indicating a widespread issue across multiple Java runtime environments that were prevalent during that time period.
The technical implementation of this vulnerability involves two distinct but related attack vectors that exploit weaknesses in how Java processes font creation and temporary file management. The first vector, identified as CR 6522586, relates to limitations in font creation processes that fail to properly constrain resource allocation when handling font files. The second vector, CR 6632886, represents an additional unspecified but related weakness that compounds the resource consumption issue. Both vectors leverage the Java runtime's handling of temporary font files, where insufficient bounds checking or resource limits allow attackers to trigger excessive disk usage through carefully crafted font data. This represents a classic resource exhaustion attack pattern that can effectively render systems unusable by consuming available storage space.
From an operational impact perspective, this vulnerability creates a severe disruption potential for systems running affected Java versions. The denial of service occurs through disk consumption rather than direct system crashes, making it particularly insidious as it can silently degrade system performance over time until storage capacity is exhausted. Organizations relying on Java applications for critical services face significant operational risks, as attackers can potentially cause cascading failures across multiple system components that depend on available disk space. The vulnerability's remote exploitability means that attackers do not require local access to cause damage, making it a particularly dangerous weakness in networked environments where Java applications are exposed to external traffic.
The underlying technical flaw aligns with CWE-400, which categorizes improper resource management as a fundamental weakness in software design. This vulnerability demonstrates how inadequate bounds checking and resource limitation mechanisms in Java's font processing libraries create opportunities for attackers to manipulate system resources through legitimate application interfaces. The attack vectors also connect to ATT&CK technique T1499.001, which covers resource exhaustion attacks specifically targeting disk space, making this vulnerability a clear example of how application-level flaws can be weaponized for denial of service purposes. Organizations should consider implementing monitoring solutions to detect unusual disk usage patterns that might indicate exploitation attempts, as well as establishing proper input validation and resource limiting mechanisms to prevent attackers from triggering the vulnerable code paths.
Mitigation strategies for this vulnerability require immediate patching of affected Java installations to versions that contain the necessary fixes for the identified font handling issues. System administrators should prioritize updating all Java installations to the latest available versions, particularly focusing on the specific update releases that address the font creation limitations and temporary file management problems. Additionally, implementing proper resource monitoring and alerting mechanisms can help detect potential exploitation attempts before they cause significant damage. Network segmentation and application whitelisting approaches can limit the attack surface by preventing unauthorized access to systems running vulnerable Java components. Organizations should also consider implementing temporary file cleanup procedures and establishing disk space thresholds that trigger automatic alerts when storage utilization approaches critical levels, providing early warning capabilities for potential exploitation attempts.