Vulnerability identifier: #VU56249

Vulnerability risk: High

CVSSv3.1: 9.4 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:H/RL:O/RC:C]

CVE-ID: CVE-2021-26084

CWE-ID: CWE-94

Exploitation vector: Network

Exploit availability: Yes

Vulnerable software:
Atlassian Confluence Server
Server applications / Web servers

Vendor: Atlassian

Description

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

The vulnerability exists due to improper input validation. A remote attacker can send a specially crafted request, perform the OGNL injection and execute arbitrary code on the system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system but requires that the "Allow people to sign up to create their account" option is enabled.

Note, as of September 3 the vulnerability is being actively exploited in the wild.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Atlassian Confluence Server: 7.11.0 - 7.11.5, 7.12.0 - 7.12.4, 7.4.0 - 7.4.10, 7.10.0 - 7.10.1, 7.6.0 - 7.6.2, 7.9.0 - 7.9.1, 7.2.0 - 7.2.2, 7.8.0 - 7.8.1, 7.7.2 - 7.7.3, 7.5.0 - 7.5.2, 7.3.1 - 7.3.5, 7.1.0 - 7.1.2, 7.0.1 - 7.0.5, 6.13.0 - 6.13.22, 6.15.1 - 6.15.10, 6.14.0 - 6.14.3, 6.12.0 - 6.12.4, 6.11.0 - 6.11.2, 6.10.0 - 6.10.3, 6.9.0 - 6.9.3, 6.8.0 - 6.8.5, 6.7.0 - 6.7.3, 6.6.0 - 6.6.17, 6.5.0 - 6.5.3, 6.4.0 - 6.4.3, 6.3.1 - 6.3.4, 6.2.0 - 6.2.4, 6.1.0 - 6.1.4, 6.0.1 - 6.0.7

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External links
http://jira.atlassian.com/browse/CONFSERVER-67940
http://packetstormsecurity.com/files/164013/Confluence-Server-7.12.4-OGNL-Injection-Remote-Code-Execution.html

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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?

Yes. This vulnerability is being exploited in the wild.