Bot or not? The fake CAPTCHA trick spreading Lumma malware. [Research Saturday}
Feb 15, 2025
auto_awesome
Nati Tal, Head of Guardio Labs, dives into the dark world of online scams with his insights on the 'DeceptionAds' campaign. He reveals how fake CAPTCHAs trick users into running malicious commands, leading to Lumma malware infections. Nati discusses the deceptive tactics that cybercriminals use to exploit trust and bypass security measures. He highlights the challenges posed by ad networks that facilitate these attacks and the ongoing battle to protect users from such insidious threats, even after takedown efforts.
The 'DeceptionAds' campaign exploits user trust in CAPTCHA by tricking them into running harmful commands that install Lumma malware.
Fragmented accountability within the ad network ecosystem complicates efforts to mitigate threats, allowing malicious ads to resurface quickly after takedown attempts.
Deep dives
Understanding Fake Captcha Campaigns
Fake captcha scams are designed to exploit users' familiarity with legitimate captcha challenges. By mimicking typical captcha activities that require users to prove they are human, threat actors trick individuals into executing harmful commands on their computers. When users believe they are completing a harmless task, they unknowingly execute malicious code that can install information-stealing malware like Luma Stealer. This method capitalizes on human tendencies to trust familiar online interactions, leading to widespread infections without users realizing their mistake.
Ad Networks as Vectors for Cyber Threats
The investigation highlights the role of ad networks in the distribution of malicious content, particularly through a specific ad network that orchestrated the fake captcha campaign. This ad network, unlike typical scenarios with multiple sources of threats, centralized the propagation of malicious ads, complicating accountability. Researchers noted that many of the ads served through this network were linked to pirated content, revealing a coordinated effort among similar publisher sites and ad network practices. Such a strategic approach makes it challenging to pinpoint the origin of the threats and address them effectively.
Fragmented Accountability in Cybersecurity
The fragmented accountability within the ad network ecosystem complicates efforts to mitigate cyber threats. With multiple organizations involved in the distribution chain, it becomes difficult to hold any single entity responsible for malicious activities, leading to a cycle where threats can quickly resurface after takedown attempts. Even when researchers successfully contact and persuade an ad network to remove harmful ads, the threat actors can rapidly adapt and reinfiltrate through different networks. This dynamic illustrates the ongoing challenge in cybersecurity, where coordinated responses are essential yet often hindered by intertwined and opaque relationships among networks.
Nati Tal, Head of Guardio Labs, discusses their work on "“DeceptionAds” — Fake Captcha Driving Infostealer Infections and a Glimpse to the Dark Side of Internet Advertising." Guardio has uncovered a large-scale malvertising campaign dubbed “DeceptionAds,” which tricks users into running a malicious PowerShell command under the guise of proving they’re human. This fake CAPTCHA scheme delivers Lumma info-stealer malware while bypassing security measures like Google’s Safe Browsing.
Even after disclosure and takedown efforts, the campaign resurfaced—raising concerns about the effectiveness of existing defenses against ad-driven cyber threats.