Details
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Bug
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Status: Resolved
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Critical
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Resolution: Fixed
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1.18
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None
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None
Description
Sonatype Nexus auditor is reporting that Jackson databind version used by Apache Tika is vulnerable. Recommendation is not to use global default typing with Jackson,
Refer following for details.
Source Sonatype Data Research
Severity Sonatype CVSS 3.0: 8.5
Weakness Sonatype CWE: 502
Explanation
jackson-databind is vulnerable to Remote Code Execution (RCE). The createBeanDeserializer() function in the BeanDeserializerFactory class allows untrusted Java objects to be deserialized. A remote attacker can exploit this by uploading a malicious serialized object that will result in RCE if the application attempts to deserialize it.
Note: This vulnerability exists due to the incomplete fix for CVE-2017-7525, CVE-2017-15095, CVE-2017-17485, CVE-2018-5968, and CVE-2018-7489. Evidence of this can be found at https://pivotal.io/security/cve-2017-4995:
Jackson provides a blacklisting approach to protecting against this type of attack, but Spring Security should be proactive against blocking unknown “deserialization gadgets” when Spring Security enables default typing.
Detection
The application is vulnerable by using this component, when default typing is enabled and passing in untrusted data to be deserialization.
Note: Spring Security has provided their own fix for this vulnerability (CVE-2017-4995). If this component is being used as part of Spring Security, then you are not vulnerable if you are running Spring Security 4.2.3.RELEASE or greater for 4.x or Spring Security 5.0.0.M2 or greater for 5.x.
Recommendation
There is no non vulnerable version of this component. We recommend investigating alternative components or a potential mitigating control.
Workaround: Do not use the default typing. Instead you will need to implement your own.
It is also possible to customize global defaulting, using ObjectMapper.setDefaultTyping(…) – you just have to implement your own TypeResolverBuilder (which is not very difficult); and by doing so, can actually configure all aspects of type information. Builder itself is just a short-cut for building actual handlers.
Reference: https://github.com/FasterXML/jackson-docs/wiki/JacksonPolymorphicDeserialization
Examples of implementing your own typing can be found by looking at Spring Security's fix or this Stack Overflow article.
Categories
Data
Root Cause
tika-app-1.18.jar <= SubTypeValidator.class : [2.9.5, )
Advisories
Attack: https://adamcaudill.com/2017/10/04/exploiting-jackson-rce-cv...
Evidence: https://pivotal.io/security/cve-2017-4995