On June 21, Red Hat officially released a security bulletin to announce the fix for a vulnerability in jackson-dababind. This vulnerability with a CVSS score of 8.1 affects multiple Red Hat products and a sophisticated exploit using this vulnerability is observed in the wild. On July 22, a security researcher named Andrea Brancaleoni published an article to analyze this vulnerability.
This vulnerability is caused by Jackson’s incomplete blacklist. An application that uses jackson-databind will become vulnerable when the enableDefaultTyping method is called via the ObjectMapper object within the application. An attacker can thus compromise the application by sending maliciously crafted JSON input to gain direct control over a server.
Currently, a proof of concept (POC) exploit for this vulnerability has been publicly available. All users who are affected by this vulnerability should upgrade to the latest versions as soon as possible to fix this issue. The following is a successful exploitation of this vulnerability.
2.Scope of Impact
- Jackson-databind 2.X < 22.214.171.124
- Jackson-databind 126.96.36.199
- Jackson-databind 2.10
If the enableDefaultTyping method is called via the ObjectMapper object within an application that uses the jackson-databind component, this application will become vulnerable. Developers are advised to check whether the jackson-databind component is used in applications, and if so, to further check its version number and whether the enableDefaultTyping method is called in the code. The following uses the Maven project as an example to show how to check the use of jackson-databind.
Check whether jackson-databind is included in xml and, if so, whether its version is earlier than 188.8.131.52.
If the answers to the preceding two questions are both “Yes”, check whether the enableDefaultTyping method is called in the code. If so, it is recommended that the component be upgraded immediately and the web application be restarted.
The vendor has fixed this vulnerability in jackson-databind 184.108.40.206. Users of this software are advised to upgrade to 220.127.116.11 or later as soon as possible to protect against this vulnerability:
Download link: https://github.com/FasterXML/jackson-databind/releases
Developers can upgrade and compile jackson-databind by configuring Maven as follows:
|<!– https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-databind –>
The new major version (3.x) of jackson-databind will address this issue via a new API layer that provides a way to achieve whitelisting-based serialization for these polymorph classes.
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