CVE-2009-1190 in JDK
Summary
by MITRE
Algorithmic complexity vulnerability in the java.util.regex.Pattern.compile method in Sun Java Development Kit (JDK) before 1.6, when used with spring.jar in SpringSource Spring Framework 1.1.0 through 2.5.6 and 3.0.0.M1 through 3.0.0.M2 and dm Server 1.0.0 through 1.0.2, allows remote attackers to cause a denial of service (CPU consumption) via serializable data with a long regex string containing multiple optional groups, a related issue to CVE-2004-2540.
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Analysis
by VulDB Data Team • 11/06/2018
The vulnerability described in CVE-2009-1190 represents a critical algorithmic complexity issue within the java.util.regex.Pattern.compile method of Sun Java Development Kit versions prior to 1.6. This flaw specifically manifests when processing serialized data containing extended regular expression patterns with multiple optional groups, creating a significant denial of service condition through excessive cpu consumption. The vulnerability operates by exploiting the inherent computational complexity of regex pattern compilation, where the time required to process certain regex patterns grows exponentially rather than linearly with input size, leading to system resource exhaustion.
The technical implementation of this vulnerability stems from the backtracking behavior of regular expression engines when handling patterns with multiple optional groups and nested quantifiers. When the java.util.regex.Pattern.compile method processes such patterns, it employs a backtracking algorithm that can explore an exponential number of possible matching paths, particularly when optional groups create multiple valid interpretations of the same input data. This behavior is exacerbated when the patterns are serialized within spring.jar files used by the Spring Framework versions mentioned in the vulnerability description. The issue is closely related to CVE-2004-2540, which established similar patterns of regex denial of service vulnerabilities in java applications, demonstrating the persistent nature of this class of vulnerability in java runtime environments.
The operational impact of CVE-2009-1190 extends beyond simple resource exhaustion to potentially compromise entire application availability and system stability. Attackers can craft malicious serialized data containing carefully constructed regex patterns that, when processed by affected java applications, cause the cpu utilization to spike dramatically while consuming system resources. This makes the vulnerability particularly dangerous in web applications, enterprise systems, and any environment where untrusted data processing occurs, as it can be exploited through various attack vectors including file uploads, network communications, or user input handling. The vulnerability affects not just individual applications but entire frameworks and platforms that rely on java's regex capabilities, creating widespread potential for system compromise and service disruption.
Mitigation strategies for CVE-2009-1190 involve multiple layers of defensive measures including immediate patching of affected JDK versions to 1.6 or later, where the regex engine implementation was significantly improved to handle such patterns more efficiently. Organizations should also implement regex pattern validation and length limits for user-supplied input, particularly when processing serialized data or external inputs that may contain regex patterns. Additionally, implementing resource monitoring and rate limiting mechanisms can help detect and prevent exploitation attempts by identifying unusual cpu consumption patterns. The vulnerability aligns with CWE-400, which categorizes algorithmic complexity vulnerabilities, and maps to ATT&CK technique T1499.004, which covers resource exhaustion attacks, emphasizing the need for comprehensive defensive measures against both the specific vulnerability and similar classes of attacks targeting computational resource consumption in java applications.