Sophos Managed Detection and Response (MDR) in September 2024, the infamous Lumma Stealer malware has developed with refined PowerShell instruments and superior evasion techniques, leveraging faux CAPTCHA websites to deceive customers.
Energetic since mid-2022 and supplied as Malware-as-a-Service (MaaS) by a presumed Russian developer, Lumma Stealer targets delicate information comparable to passwords, session tokens, cryptocurrency wallets, and private info.
What makes this newest marketing campaign notably insidious is its use of social engineering, exploiting person belief in CAPTCHA challenges to execute malicious PowerShell instructions, usually resulting in devastating information theft.
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PowerShell-Pushed Payloads
Sophos MDR investigations carried out by way of the autumn and winter of 2024-25 reveal the intricate mechanics behind Lumma Stealer’s supply.
One outstanding assault vector entails customers being redirected to seemingly authentic CAPTCHA verification pages that immediate them to stick a malicious PowerShell command into Home windows’ Run dialog field or command-line interface.
This command, usually hidden behind obfuscated JavaScript, retrieves a script from a distant server, comparable to “fixedzip.oss-ap-southeast-5.aliyuncs.com,” which then downloads a zipped payload disguised as “ArtistSponsorship.exe.”
In accordance with Sophos Report, this executable drops a number of recordsdata, together with an obfuscated AutoIt script, into the person’s %temp% listing.
The script connects to command-and-control (C2) servers like “snail-r1ced.cyou” (IP 104.21.84.251 through Cloudflare) to exfiltrate stolen information, together with Chrome login credentials and cookies, with alarming precision.
In a single noticed case, a mere 6.37MB file of delicate information was efficiently transmitted earlier than the method self-terminated.
One other variant entails tricking customers into opening a supposed PDF file that’s really a remotely hosted .lnk shortcut, triggering a deeply obfuscated PowerShell script.
This script makes use of AES encryption and dynamic API decision with instruments like CyberChef revealing a transportable executable (PE) file designed to obtain additional payloads whereas masking its intent by way of layers of base64 encoding and misleading file paths in %appdata%.
The complexity of those evasion strategies, together with dynamic loading of malicious code through .NET’s System.Reflection.Meeting class and the usage of legitimate-looking IRS PDFs as decoys, underscores the stealer’s means to bypass conventional defenses.
A Rising Menace Panorama for Defenders
The adaptability of Lumma Stealer’s supply strategies poses a major problem for cybersecurity defenders.
Experiences from Netskope Menace Labs estimate round 5,000 faux CAPTCHA websites could also be lively on this marketing campaign, amplifying the menace’s attain.
Nevertheless, the evolving tactics-combining person manipulation with technical sophistication-highlight the necessity for strong endpoint safety and person schooling.
Reversing years of ingrained belief in CAPTCHA prompts is a frightening process, but it surely’s essential as attackers proceed to take advantage of this familiarity.
As Lumma Stealer stays a pervasive menace in 2025, organizations should deploy superior behavioral evaluation and scrutinize community exercise for indicators of C2 communication or information exfiltration to remain forward of this crafty infostealer.
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