CVE-2023-34040
Published: 24 August 2023
Summary
CVE-2023-34040 is a medium-severity Deserialization of Untrusted Data (CWE-502) vulnerability in Vmware Spring For Apache Kafka. Its CVSS base score is 5.3 (Medium).
Operationally, ranked in the top 4.2% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
Deeper analysis
In Spring for Apache Kafka versions 3.0.9 and earlier as well as 2.9.10 and earlier, a deserialization vulnerability exists that could allow attacks via malicious serialized objects placed in deserialization exception record headers. The issue arises under specific configurations where ErrorHandlingDeserializer is not used for keys or values, and the checkDeserExWhenKeyNull or checkDeserExWhenValueNull properties are set to true.
An attacker able to publish messages to a Kafka topic from an untrusted source could supply crafted headers that trigger unsafe deserialization when those container properties are enabled, resulting in local impacts rated at CVSS 5.3 under CWE-502.
Spring advisory guidance states that the relevant container properties default to false and that the container only processes such headers when an ErrorHandlingDeserializer is configured; the ErrorHandlingDeserializer itself blocks the attack by removing malicious headers prior to record handling.
The associated EPSS score rose from lower values to a peak of 0.2736, indicating that exploitation interest emerged after disclosure.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2023-2275
Vulnerability details
In Spring for Apache Kafka 3.0.9 and earlier and versions 2.9.10 and earlier, a possible deserialization attack vector existed, but only if unusual configuration was applied. An attacker would have to construct a malicious serialized object in one of the…
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deserialization exception record headers. Specifically, an application is vulnerable when all of the following are true: * The user does not configure an ErrorHandlingDeserializer for the key and/or value of the record * The user explicitly sets container properties checkDeserExWhenKeyNull and/or checkDeserExWhenValueNull container properties to true. * The user allows untrusted sources to publish to a Kafka topic By default, these properties are false, and the container only attempts to deserialize the headers if an ErrorHandlingDeserializer is configured. The ErrorHandlingDeserializer prevents the vulnerability by removing any such malicious headers before processing the record.
- CWE(s)
Related Threats
No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Penetration testing supplies malicious serialized objects, detecting unsafe deserialization and supporting corrective actions.
Evaluation of untrusted data handling (deserialization testing) reveals unsafe processing, which the required remediation process addresses.
Untrusted serialized data can be deserialized and observed inside the chamber, blocking gadget-chain exploitation outside the sandbox.
Validates or rejects untrusted serialized data before deserialization occurs.
Identifies and blocks malicious code introduced through deserialization of untrusted data at system boundaries.
Integrity verification of serialized information can detect tampering before deserialization occurs.
Provenance of associated data allows detection of untrusted sources before deserialization or processing occurs.