CVE-2007-0243 in Java JRE
Summary
by MITRE
Buffer overflow in Sun JDK and Java Runtime Environment (JRE) 5.0 Update 9 and earlier, SDK and JRE 1.4.2_12 and earlier, and SDK and JRE 1.3.1_18 and earlier allows applets to gain privileges via a GIF image with a block with a 0 width field, which triggers memory corruption.
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Analysis
by VulDB Data Team • 01/25/2025
The vulnerability described in CVE-2007-0243 represents a critical buffer overflow flaw affecting multiple versions of the Sun Java Development Kit and Java Runtime Environment across different major releases. This vulnerability specifically targets the GIF image parsing functionality within the Java runtime environment, creating a pathway for malicious applets to execute arbitrary code with elevated privileges. The flaw manifests when processing GIF images containing malformed blocks with zero width fields, which causes the Java runtime to improperly handle memory allocation and data copying operations.
The technical implementation of this vulnerability stems from inadequate input validation within the GIF decoder component of the Java runtime. When a GIF image is processed by a Java applet, the system attempts to parse the image data structure including various blocks such as the Graphics Control Extension. The buffer overflow occurs specifically when the width field of a GIF block is set to zero, which triggers an improper calculation of memory requirements for subsequent data processing. This leads to memory corruption as the system attempts to copy data beyond the allocated buffer boundaries, potentially overwriting adjacent memory locations including critical program structures and security controls.
From an operational perspective, this vulnerability presents a significant risk to Java-based web applications and applet deployments. The attack vector involves a malicious GIF image embedded within a web page that, when loaded by a vulnerable Java runtime, can execute arbitrary code with the privileges of the user running the Java application. This privilege escalation capability enables attackers to perform actions such as reading sensitive files, modifying system configurations, or establishing persistent access to affected systems. The vulnerability affects multiple Java versions simultaneously, making it particularly dangerous for organizations maintaining legacy systems that have not been updated to patched releases.
The impact of this vulnerability aligns with CWE-121, which categorizes buffer overflow conditions as critical security weaknesses that can lead to arbitrary code execution. From an attack framework perspective, this vulnerability would typically be classified under the attack technique of code injection, specifically targeting the runtime environment's image processing capabilities. The vulnerability's exploitation requires minimal user interaction beyond visiting a malicious webpage containing the compromised GIF image, making it particularly dangerous for widespread deployment. Organizations should implement immediate mitigations including updating to patched Java versions, disabling Java applets in web browsers, or implementing network-level restrictions to prevent access to potentially malicious content.
Security practitioners should recognize that this vulnerability represents a classic example of how image parsing libraries can introduce critical security risks when proper bounds checking is not implemented. The vulnerability demonstrates the importance of input validation and memory safety practices in security-critical components of runtime environments. Mitigation strategies should include comprehensive patch management programs, regular security assessments of Java-based applications, and implementation of web application firewalls to filter potentially malicious content. Organizations should also consider deploying sandboxing technologies to isolate Java applet execution and reduce the potential impact of successful exploitation attempts. The vulnerability highlights the ongoing need for security-conscious development practices and thorough testing of input processing components in enterprise software environments.