SilentFade’ Attack Drained Facebook Victims of $4M
Facebook has detailed a wide-scale Chinese malware campaign that targeted its ad platform for years and siphoned $4 million from users’ advertising accounts. It was dubbed “SilentFade” (short for “Silently running Facebook Ads with Exploits”) the malware compromised Facebook accounts and used them to promote malicious ads, steal browser cookies and more. The social-media giant said that the Chinese malware campaign started in 2016, but it was first discovered in December 2018, due to a suspicious traffic spike across a number of Facebook endpoints. After an extensive investigation, Facebook shut down the campaign and pursued legal action against the cybercriminals behind the attack in December 2019.
Once installed, SilentFade stole Facebook credentials and cookies from various browser credential stores, including Internet Explorer, Chromium and Firefox.
The malware itself consists of three to four components, with the main downloader component being included in PUP bundles, researchers said. This downloader component is either a standalone malware component or a Windows service (installed as either “AdService” or ‘”HNService”). It’s responsible for persistence across reboots and for dropping 32-bit and 64-bit version dynamic library links (DLLs) in Chrome’s application dAfter stealing credentials, the malware retrieves the metadata about the Facebook account (such as payment information and the total amount previously spent on Facebook ads), using the Facebook Graph API, which is a legitimate Facebook feature allowing users to read and write data to and from the Facebook social graph. This data is then sent back to the malware’s C2 servers (as an encrypted JSON blob through custom HTTP headers).
And, in a unique anti-detection tactic, the C2 server stores the data and logs the IP address of the incoming request for the purpose of geolocation. “This was crucial as the attackers intentionally used the stolen credentials from the same or a nearby city to the infected machine to appear as though the original account owner has traveled within their city,” said researchers.
However, it should be noted that payment-information details (such as bank account and credit card numbers) were never exposed to the attackers, as Facebook does not make them visible through the desktop website or the Graph API.