Vulnerability identifier: #VU21323

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-2019-16759

CWE-ID: CWE-78

Exploitation vector: Network

Exploit availability: Yes

Vulnerable software:
vBulletin
Web applications / Forum & blogging software

Vendor: vBulletin

Description

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

The vulnerability exists due to improper input validation in "ajax/render/widget_php" when processing data passed via the "widgetConfig[code]" HTTP POST parameter. A remote unauthenticated attacker can send specially crafted HTTP POST request to the affected application and execute arbitrary OS commands on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Note: The vulnerability is being actively exploited in the wild.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

vBulletin: 5.0 - 5.5.4

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External links
http://seclists.org/fulldisclosure/2019/Sep/31
http://www.exploit-db.com/exploits/47447
http://forum.vbulletin.com/forum/vbulletin-announcements/vbulletin-announcements_aa/4422707-vbullet...

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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.