Connect with us

Hi, what are you looking for?

SecurityWeekSecurityWeek

Malware & Threats

‘Sys01 Stealer’ Malware Targeting Government Employees

The Sys01 Stealer has been observed targeting the Facebook accounts of critical government infrastructure employees.

Endpoint security firm Morphisec has shared details on an information stealer that has been observed targeting the Facebook accounts of critical government infrastructure employees.

Dubbed Sys01 Stealer, the malware is distributed via Google ads and fake Facebook accounts promoting adult content, games, and cracked software, and is executed on the victim’s machine using DLL side-loading.

Last month, Bitdefender detailed similar distribution and execution techniques being used by the ‘S1deload Stealer’, which targets Facebook and YouTube accounts for data harvesting. The final payload, however, is different, Morphisec notes.

Since November 2022, Sys01 Stealer has targeted employees in various industries, including government and manufacturing, focused on exfiltrating information such as credentials, cookies, and Facebook ad and business account data.

Victims are lured into clicking a URL from an ad or a fake Facebook account to download a ZIP archive claiming to contain a movie, a game, or an application.

The archive contains a loader, which is a legitimate application vulnerable to DLL side-loading, and a malicious library that is side-loaded to drop the Inno-Setup installer, which in turn deploys the final payload in the form of a PHP application containing malicious scripts for data harvesting and exfiltration.

A PHP script is responsible for achieving persistence, by setting a scheduled task, while the main stealer script includes support for various tasks, including allowing the attackers to check whether the victim has a Facebook account, and whether they are logged in.

The script also supports the download and execution of files from a specified URL, can upload files to the command-and-control (C&C) server, and can execute commands.

Advertisement. Scroll to continue reading.

Morphisec’s analysis of the threat also revealed the use of Rust, Python, PHP, and PHP advanced encoders that helped the information stealer remain undetected for the past five months.

“Basic steps to help prevent Sys01 stealer include implementing a zero-trust policy and limiting users’ rights to download and install programs. And Sys01 stealer at heart relies on a social engineering campaign, so it’s important to train users about the tricks adversaries use so they know how to spot them,” Morphisec concludes.

Related: New ‘RisePro’ Infostealer Increasingly Popular Among Cybercriminals

Related: Multi-Purpose Botnet and Infostealer ‘Aurora’ Rising to Fame

Related: Hundreds Infected With ‘Wasp’ Stealer in Ongoing Supply Chain Attack

Written By

Ionut Arghire is an international correspondent for SecurityWeek.

Click to comment

Trending

Daily Briefing Newsletter

Subscribe to the SecurityWeek Email Briefing to stay informed on the latest threats, trends, and technology, along with insightful columns from industry experts.

Learn how the LOtL threat landscape has evolved, why traditional endpoint hardening methods fall short, and how adaptive, user-aware approaches can reduce risk.

Watch Now

Join the summit to explore critical threats to public cloud infrastructure, APIs, and identity systems through discussions, case studies, and insights into emerging technologies like AI and LLMs.

Register

People on the Move

Checkmarx has appointed Scott Gainey as Chief Marketing Officer.

Jason Hogg has been named Executive Chairman of CYPFER.

HUB Cyber Security has appointed former PayPal and American Express executive Paul Parisi as its Global Chief Revenue Officer.

More People On The Move

Expert Insights

Daily Briefing Newsletter

Subscribe to the SecurityWeek Email Briefing to stay informed on the latest cybersecurity news, threats, and expert insights. Unsubscribe at any time.