Exploits for vBulletin zero-day released, attacks are ongoing
Vulnerabilities mentionedAll →
| CVE | Vulnerability | CVSS | EPSS | Flags | Affected | Exposure | Published |
|---|---|---|---|---|---|---|---|
| CVE-2019-16759 | Pre-Authentication Remote Code Execution in vBulletin 5.x CVE-2019-16759 is a critical (CVSS 9.8) unauthenticated remote code execution flaw in vBulletin 5.x through 5.5.4 (CWE-94, code injection) in the PHP widget rendering component. An attacker triggers it by sending a crafted request to the 'ajax/render/widget_php' routestring with a malicious PHP payload in the widgetConfig[code] parameter, requiring no credentials or user interaction. Successful exploitation yields remote command execution on the web server as the web application user, enabling full compromise of the forum, theft or modification of its user database, and a foothold for further network access. Any site running vBulletin 5.x through 5.5.4 is affected, and exploitation is confirmed in the wild: the flaw was attacked as a zero-day after public exploits appeared, with headline-reported compromises including the Comodo Forums breach affecting about 245,000 users and the ZoneAlarm forum hack, and botnets observed exploiting the flaw. It is listed in CISA KEV (added 2021-11-03) with a 99.7% EPSS score, indicating near-certain near-term exploitation probability. Do: Upgrade vBulletin to a release newer than 5.5.4 (the patched 5.5.x version per vendor instructions), as required by the CISA KEV action. As an interim mitigation, block or filter requests to the 'ajax/render/widget_php' routestring (or strip the widgetConfig[code] parameter) at the web server or WAF. Because exploitation requires no authentication and public PoC exploits are widely available, assume compromise and check logs for requests to ajax/render/widget_php containing widgetConfig[code], and investigate any forum for signs of data theft or web shell implantation. | 9.8 | 100% | KEV PoC ×9 |
| largetens of thousands of internet-exposed vBulletin 5.x forum installations (plausibly 10k–100k+ sites, translating to hundreds of thousands to millions of forum… |
Full article361 words · extracted from helpnetsecurity.com · click to collapse
The fix for CVE-2019-16759, a remote code execution vulnerability in vBulletin that was patched in September 2019, is incomplete, security researcher Amir Etemadieh has discovered.
The discovery and his publishing of PoC and full exploits spurred attackers to launch attacks:
A new VBulletin Zero Day got dropped yesterday by @Zenofex that revealed the CVE-2019-16759 patch was incomplete – within three hours https://t.co/LwbPuEoL5b was attacked, but we were ready for it. Disable PHP rendering to protect yourself until patched! https://t.co/7JtmEzcTFG pic.twitter.com/R4AcCoZt1B
— Jeff Moss (@thedarktangent) August 10, 2020
Several other admins confirmed that they’ve been hit.
Risk mitigation and prevention
Etemadieh explained how he discovered that the patch for CVE-2019-16759 was flawed in a blog post published on Sunday.
Today I released my research on vBulletin5 including a new pre-auth 0day RCE exploithttps://t.co/m7pd527lCr
POC: curl -s http://SITE/ajax/render/widget_tabbedcontainer_tab_panel -d 'subWidgets[0][template]=widget_php&subWidgets[0][config][code]=echo%20shell_exec("id"); exit;' pic.twitter.com/JjThUBVTmc
— Amir Etemadieh (@Zenofex) August 9, 2020
It’s a quality write-up and contains a one-line PoC exploit and full exploits written Bash, Python and Ruby, as well as instructions on how to implement a fix until a more complete patch is released (in short, forum admins were advised to temporarily disable PHP widgets).
“Tenable Research has tested the proof of concept from Etemadieh and confirmed successful exploitation using the latest version of vBulletin,” Tenable research engineer Satnam Narang confirmed .
Internet Brands, the makers of vBulletin, have not been notified of this discovery prior to the publication, so they’ve scrambled to fix the flaw again.
New patches have been made available on Monday, for versions 5.6.2, 5.6.1 and 5.6.0 of vBulletin Connect, and they disable the PHP Module widget. The upcoming v5.6.3 will contain the patch.
“All older versions should be considered vulnerable. Sites running older versions of vBulletin need to be upgraded to vBulletin 5.6.2 as soon as possible,” they advised, and noted that vBulletin Cloud sites are not affected by this issue.
vBulletin is the most popular internet forum software in use today and also powers many dark web forums. vBulletin flaws, especially when they allow remote code execution without authentication, are usually speedily leveraged by attackers, so admins are advised to implement the patches ASAP.
Text extracted automatically; images, tables and formatting may be missing. Original: https://www.helpnetsecurity.com/2020/08/11/fix-cve-2019-16759/