In a warning Thursday, the FBI warns security agencies and professionals about this tactic adopted by FIN7 to deliver GRIFFON malware.
The attack is a variation of the "lost USB" ruse that penetration testers used for several years in their evaluations quite successfully and an incident was analyzed by them. researchers by Trustwave.
A cybersecurity customer received a package, allegedly from Best Buy, containing a $ 50 gift card. In the envelope there was a USB drive that claimed to contain a list of products that were eligible for purchase using the gift card.
However, this is not a one-off incident.
The FBI warns that FIN7 has sent these packages to many businesses (retailers, restaurants, hotels) that target employees in human resources, IT or management departments.
Recently, the FIN7,1 computer group, known for targeting such businesses via phishing messages (Phishing), used an additional tactic for sending USB devices through the United States Postal Service (USPS). Packages sometimes include items such as teddy bears or gift cards to targeted employees companies working in the departments of Human Resources, Computer Science (IT) or the Executive Command (EM), "the FBI warns.
The FBI says the malicious unit is configured to simulate keystrokes that launch a PowerShell command in order to recover malware from intruder-controlled servers. The USB device then communicates with domain or IP addresses in Russia.
The days when USB flash drives were just for storage are long gone. Several development tables (Teensy, Arduino) are now available for programming to mimic a human interface device (HID) such as keyboards and mice and launch a predefined set of keys to drop malicious payloads. These are called HID or USB drive-by attacks that are easy to perform and do not cost much.
To better summarize the attack flow, the researchers created the following image, which clarifies the stages of compromise that led to the development of malware by the intruder choice.
The FBI notice informs that after the identification phase the hacker begins to move sideways seeking their privileges. admin.
FIN7 uses multiple tools to achieve its goal. The list includes Metasploit, Cobalt Strike, PowerShell scripts, Carbanak malware, Griffon backdoor, malicious Boostwrite dropper and remote-control RdfSniffer module access.
BadUSB attacks, proven by security researcher Karsten Nohl in 2014, are more common in penetration testing and there are many alternatives these days. The most flexible are priced at $ 100.
FIN7 went with a simple and inexpensive version, however, which costs between $ 5- $ 14, depending on the vendor and country shipping. The FBI notes in its warning that the microcontroller is an ATMEGA24U, while the one watching Trustwave had an ATMEGA32U4.
However, both variants were printed on the "HW-374" circuit board and are identified as an Arduino Leonardo, which is specially programmed to function as a keyboard / mouse. Customizing mouse keys and gestures is possible using the Arduino IDE.
Connecting unknown USB devices to one workstation is a well-known security risk, but is still ignored by many users.
Organizations can take precautionary attacks against malicious USB drives, allowing access only to devices controlled by their hardware ID and denying access to all others.