2021-21345 | Oracle WebCenter Portal XStream code injection

By Max On Jul 24, 2021

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
9.5	$5k-$25k	0.38

A vulnerability classified as very critical was found in Oracle WebCenter Portal 11.1.1.9.0/12.2.1.3.0/12.2.1.4.0 (Content Management System). Affected by this vulnerability is some unknown functionality of the component XStream. The manipulation with an unknown input leads to a privilege escalation vulnerability. The CWE definition for the vulnerability is CWE-94. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

XStream is a Java library to serialize objects to XML and back again. In XStream before version 1.4.16, there is a vulnerability which may allow a remote attacker who has sufficient rights to execute commands of the host only by manipulating the processed input stream. No user is affected, who followed the recommendation to setup XStream’s security framework with a whitelist limited to the minimal required types. If you rely on XStream’s default blacklist of the Security Framework, you will have to use at least version 1.4.16.

The weakness was presented 07/20/2021 as Oracle Critical Patch Update Advisory – July 2021. It is possible to read the advisory at oracle.com. This vulnerability is known as CVE-2021-21345 since 12/22/2020. The exploitation appears to be easy. The attack can be launched remotely. A single authentication is required for exploitation. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 07/24/2021).

We expect the 0-day to have been worth approximately $25k-$100k.

Upgrading eliminates this vulnerability. A possible mitigation has been published immediately after the disclosure of the vulnerability.

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