#VU28158 Deserialization of Untrusted Data in Apache Tomcat - CVE-2020-9484

Vulnerability identifier: #VU28158

Vulnerability risk: High

CVSSv4.0: 8.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/U:Amber]

CVE-ID: CVE-2020-9484

CWE-ID: CWE-502

Exploitation vector: Network

Exploit availability: Yes

Vulnerable software:
Apache Tomcat
Server applications / Web servers

Vendor: Apache Foundation

Description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to insecure input validation when processing serialized data in uploaded files names. A remote attacker can pass specially crafted file name to the application and execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system but requires that the server is configured to use PersistenceManager with a FileStore and the attacker knows relative file path from storage location.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Apache Tomcat: 7.0.0 - 7.0.103, 8.0.0 RC1 - 8.0.53, 8.5.0 - 8.5.54, 9.0.0-M1 - 9.0.34, 10.0.0-M1 - 10.0.0.0-M1

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External links
https://lists.apache.org/thread.html/r77eae567ed829da9012cadb29af17f2df8fa23bf66faf88229857bb1%40%3Cannounce.tomcat.apache.org%3E

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.