GHSA-h84g-69h7-mw6v

### Impact Prior to version 0.6.0, mchange-commons-java includes a JNDI `ObjectFactory` implementation (`com.mchange.v2.naming.JavaBeanObjectFactory`) willing to construct objects of arbitrary classes and initialize "JavaBean"-style properties. There are classes for which this kind of initialization is unsafe. For example, setting the "contentType" property of a Swing `JEditorPane` to `text/html` and the "text" property to HTML containing a stylesheet <link> will provoke an HTTP GET on an arbitrary URL, potentially from within a trusted security domain. This issue is aggravated by mchange-commons-java's `ReferenceIndirector`, by which malicious JNDI `Reference` objects could be smuggled in for dereferencing by applications anywhere a Java-serialized object might be read.

Prior to version 0.5.0, the same mchange-commons-java `ObjectFactory` would interpret `BinaryRefAddress` elements as Java-serialized objects, and deserialize unexpected objects that potentially execute malicious behavior on initialization. Although this author is unaware of any code within mchange-commons-java itself that can be abused to execute code on deserialization, this mechanism can be used to trigger well-known "deserialization gadget chains" involving other libraries. For example, in JVMs prior to Java 16 with Apache libraries [`commons-beanutils`](https://commons.apache.org/proper/commons-beanutils/) and [`commons-collections`](https://commons.apache.org/proper/commons-collections/) on the application `CLASSPATH`, [objects can be crafted](https://gist.github.com/frohoff/9eb8811761ff989b3ac0) that will execute arbitrary commands on deserialization. (Thanks to Valerio Mulas for a proof-of-concept.)

### Patches mchange-commons-java v0.5.0 eliminates all support for deserializing Java objects in `com.mchange.v2.naming.JavaBeanObjectFactory`, unless an application explicitly extends that class to restore it. This prevents mchange-commons-java from enabling JNDI injection to trigger common "deserialization gadgets".

mchange-commons-java v0.6.0 imposes a whitelist upon what classes `com.mchange.v2.naming.JavaBeanObjectFactory` consents to materialize, preventing the use of maliciously constructed `Reference` instances to initialize arbitrary, potentially malicious, objects.

mchange-commons-java v0.6.0 disables the `ReferenceIndirector` mechanism by default. This mechanism has been abused by attackers to inject dangerous JNDI `Reference` objects by causing an application to deserialize a malicious Java-serialized object. (The functionality remains for applications that need it, gated behind a restrictive configuration parameter. This is "defense-in-depth"; the hardening of `JavaBeanObjectFactory` on its own should be sufficient to prevent known `Reference`-based attacks. But perhaps there are other insecure `ObjectFactory` implementations on the `CLASSPATH` or vulnerabilities as-yet-unknown.)

### Workarounds Upgrading to the current version of mchange-commons-java is strongly recommended. Most applications that install mchange-commons-java do so to support the c3p0 JDBC Connection pooling library. When upgrading mchange-commons-java, be sure to update c3p0 as well, or better yet, upgrade to c3p0 >=v0.14.0 and bring in a patched mchange-commons-java transitively.

Maintaining rigorous serialization filters can prevent many attacks (but not attacks requiring only construction of a named class and initialization of simple JavaBeans properties, as described for `JEditorPane` above).

The vulnerabilities that this advisory addresses all begin with arranging for an application to lookup a malicious JNDI `Reference` or deserialize a malicious Java-serialized object. Assiduously preventing an application from ever encountering such a `Reference` or serialized object is hypothetically a workaround. But relying upon perfection is usually bad planning.

The most common known attacks rely upon JVM-internal XSLT code that has been made inaccessible on Java 16 and beyond. Running on a more recent JVM is a mitigating workaround.

### Resources The vulnerabilities and security upgrades are documented in c3p0's manual. Please see c3p0's [Security Note](https://www.mchange.com/projects/c3p0/#security-note) and [Configuring Security](https://www.mchange.com/projects/c3p0/#configuring_security).

### Credits mchange-commons-java thanks 4ra1n and unam4 on Github for a proof-of-concept.