1 Vulnerability Description
On September 18, a security researcher submitted Fastjson remediation code on Alibaba’s official GitHub to prevent new exploits of the Fastjson deserialization remote code execution vulnerability. An attacker could exploit this vulnerability to remotely execute malicious code to compromise the server.
Fastjson is an open-source JSON library developed by Alibaba to parse JOSN strings. It can be used to serialize JavaBean into a JSON string and deserialize a JSON string to JavaBean. Fastjson works efficiently and therefore is widely used. Users should take preventive measures as soon as possible.
Reference:
https://github.com/alibaba/fastjson/commit/05a7aa7f748115018747f7676fd2aefdc545d17a
2 Scope of Impact
Affected Versions
Fastjson 1.2.60 and earlier
Unaffected Versions
None
3 Mitigation
Workarounds
Currently, there has been no official release to fix this vulnerability. Affected users must make sure that they have upgraded to the latest version and should disable the AutoType function (disabled by default) to protect against this vulnerability.
Users can disable the AutoType function in either of the following ways:
- Find the following code in the source code and delete it:
ParserConfig.getGlobalInstance().setAutoTypeSupport(true);
- When enabling Fastjson on a Java virtual machine, remember not to add the following parameter:
-Dfastjson.parser.autoTypeSupport=true
Once an official security update is released, affected users should apply it as soon as possible to protect against this vulnerability.
Statement
This advisory is only used to describe a potential risk. NSFOCUS does not provide any commitment or promise on this advisory. NSFOCUS and the author will not bear any liability for any direct and/or indirect consequences and losses caused by transmitting and/or using this advisory. NSFOCUS reserves all the rights to modify and interpret this advisory. Please include this statement paragraph when reproducing or transferring this advisory. Do not modify this advisory, add/delete any information to/from it, or use this advisory for commercial purposes without permission from NSFOCUS.
About NSFOCUS
NSFOCUS, Inc., a global network and cyber security leader, protects enterprises and carriers from advanced cyber attacks. The company’s Intelligent Hybrid Security strategy utilizes both cloud and on-premises security platforms, built on a foundation of real-time global threat intelligence, to provide multi-layered, unified and dynamic protection against advanced cyber attacks.
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