Deserialization Flaw in c3p0 JDBC Connection Pool

Executive Summary

This vulnerability involves the c3p0 JDBC Connection pooling library versions prior to 0.14.0. When used with other libraries, c3p0 can act as a "sink" for deserialization gadgets. Specifically, JavaBean libraries treat methods like DataSource.getConnection() and ConnectionPoolDataSource.getPooledConnection() as safe properties, but these methods actually invoke JDBC drivers. Attackers can craft malicious DataSource objects that exploit this behavior by embedding them in serialized form. When an application deserializes these objects and automatically resolves bean properties, it triggers the attack. This requires a vulnerable DataSource/ConnectionPoolDataSource and JDBC driver on the classpath, along with a component that auto-looks-up JavaBean properties during deserialization, such as a collection sorted by an Apache commons-beanutils Comparator. The vulnerable c3p0 DataSource/ConnectionPoolDataSource was a key part of this exploit. The issue was fixed in c3p0 version 0.14.0.

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Detection Guidance

This vulnerability involves the deserialization of malicious DataSource objects that trigger JavaBean property lookups, which is a behavior occurring within Java applications using c3p0 versions prior to 0.14.0 combined with vulnerable JDBC drivers and certain libraries.

Detection on a network or system level is challenging because the attack is triggered internally during Java object deserialization and bean property introspection, rather than through obvious network signatures.

To detect if your system is vulnerable, you should:

• Check the version of c3p0 used in your Java applications. Versions prior to 0.14.0 are vulnerable.
• Identify if your application uses JDBC DataSource or ConnectionPoolDataSource implementations from c3p0.
• Verify if your application deserializes objects that might include DataSource instances and if it uses libraries that perform automatic JavaBean property lookups on deserialization, such as Apache Commons BeanUtils Comparator.

Suggested commands to assist in detection include:

• Use dependency management tools to check c3p0 version, e.g., for Maven: mvn dependency:tree | grep c3p0
• Search your codebase for usage of c3p0 DataSource classes: grep -r 'com.mchange.v2.c3p0' ./
• Check running Java processes for c3p0 version by inspecting the JAR manifest or using jcmd or jps combined with jinfo or jcmd to inspect classpath.
• Monitor application logs for suspicious deserialization activity or exceptions related to bean property introspection.

Because the attack vector is internal to Java deserialization and bean introspection, network-level detection commands are not straightforward or effective.

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Impact Analysis

This vulnerability can allow attackers to execute malicious code during the deserialization process by exploiting the way c3p0 and other libraries handle JavaBean property lookups. This can lead to unauthorized actions, potentially compromising the security of the application, exposing sensitive data, or allowing further attacks within the system.

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Compliance Impact

The provided information does not explicitly address how this vulnerability impacts compliance with common standards and regulations such as GDPR or HIPAA.

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Mitigation Strategies

To mitigate this vulnerability, upgrade the c3p0 library to version 0.14.0 or later, where the issue has been fixed.

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