The connection to Keksec comes from overlaps in the domains that were previously identified as used by the malware group. Zimperium attributed the malware to a threat actor tracked as Keksec (aka Kek Security, Necro, and FreakOut), which has a history of developing a wide range of botnet malware, including EnemyBot, for crypto mining and DDoS operations. The script further acts as a keylogger and a conduit for launching additional commands received from a remote server, allowing it to steal clipboard data, browser cookies, and mount layer 7 DDoS attacks against any domain. This attack chain, in turn, exploits flaws in web browsers such as Mozilla Firefox ( CVE-2019-11708, CVE-2019-9810), Internet Explorer ( CVE-2014-6332, CVE-2016-0189), and Edge ( CVE-2016-7200) to escape the browser sandbox and deploy malware on the system. The JavaScript code takes responsibility for cryptojacking operations, abusing the victim's computing resources to illicitly mine cryptocurrencies, as well as inject a second script named 'cthulhu.js.' Once installed, the extension is designed to inject a JavaScript file called 'campaign.js' on all pages, meaning the malware could also operate as a standalone piece of code on any website, legitimate or otherwise, potentially leading to watering hole attacks.

The JavaScript botnet isn't distributed via Chrome Web Store or Microsoft Edge Add-ons, but rather through fake executables and rogue websites disguised as Adobe Flash Player updates.

The extension 'not only steals the information available during the browser session but can also install malware on a user's device and subsequently assume control of the entire device,' Zimperium researcher Nipun Gupta said in a new report. The Keksec threat actor has been linked to a previously undocumented malware strain, which has been observed in the wild masquerading as an extension for Chromium-based web browsers to enslave compromised machines into a botnet.Ĭalled Cloud9 by security firm Zimperium, the malicious browser add-on comes with a wide range of features that enables it to siphon cookies, log keystrokes, inject arbitrary JavaScript code, mine crypto, and even enlist the host to carry out DDoS attacks.

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