CVE-2009-2675 in JRE
Summary
by MITRE
Integer overflow in the unpack200 utility in Sun Java Runtime Environment (JRE) in JDK and JRE 6 before Update 15, and JDK and JRE 5.0 before Update 20, allows context-dependent attackers to gain privileges via unspecified length fields in the header of a Pack200-compressed JAR file, which leads to a heap-based buffer overflow during decompression.
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Analysis
by VulDB Data Team • 04/07/2025
The vulnerability identified as CVE-2009-2675 represents a critical integer overflow condition within the unpack200 utility of Sun Java Runtime Environment implementations. This flaw exists in specific versions of JDK and JRE where the utility processes Pack200-compressed JAR files, creating a scenario where maliciously crafted archive headers can trigger unintended memory behavior. The vulnerability specifically targets the handling of length fields within the Pack200 file format header structure, which serves as the foundation for decompression operations in Java application deployment.
The technical implementation of this vulnerability stems from inadequate input validation within the unpack200 utility's parsing logic. When processing Pack200-compressed JAR files, the utility reads length fields that define the size of various data structures within the archive header. An attacker can manipulate these fields to contain values that exceed the maximum representable integer value for the system architecture, causing an integer overflow condition. This overflow subsequently results in a heap-based buffer overflow during the decompression process, as the utility attempts to allocate memory based on the corrupted length values.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential remote code execution capabilities. Attackers can leverage this flaw by crafting malicious Pack200-compressed JAR files that contain specially constructed header fields designed to trigger the integer overflow condition. When a victim system processes such a file through the unpack200 utility, either during application deployment or automatic processing, the resulting buffer overflow can be exploited to execute arbitrary code with the privileges of the affected Java process. This represents a significant threat vector in environments where Java applications automatically process untrusted archive files.
The vulnerability aligns with CWE-190, Integer Overflow or Wraparound, which specifically addresses issues where integer arithmetic results in values that exceed the maximum representable value for the data type. This classification emphasizes the fundamental nature of the flaw as a mathematical overflow condition that propagates into memory management issues. Additionally, the attack pattern corresponds to techniques described in MITRE ATT&CK framework under T1059.007 for Unix Shell and T1059.006 for Windows Command Shell, as successful exploitation would likely involve command execution through compromised Java processes. Organizations should implement immediate mitigation strategies including patching affected systems, disabling automatic processing of Pack200 files, and implementing network-level controls to prevent the delivery of malicious JAR archives. The vulnerability underscores the critical importance of input validation in security-sensitive applications and demonstrates how seemingly benign file processing utilities can become attack vectors when proper boundary checking is absent.