A study by Group-IB, the cybersecurity firm, has revealed that a new type of ransomware attack, known as ProLock, emerged in recent months by raising red flags among the cybersecurity community and authorities such as the FBI in the US, which comes in the form of a Trojan.
On May 17, it has been reported that ProLock relies on the Qakbot banking trojan to launch the attack and asks the targets for six-figure USD ransoms paid out in BTC to decrypt the files.
However, the roster of victims includes local governments, financial, healthcare, and retail organizations. Among them, the attack, which Group-IB considers the most notable was against ATM provider Diebold Nixdorf.
ProLock Ransomware teams up with QakBot trojan for network access – @Ionut_Ilascuhttps://t.co/YIRcbIKnyc — BleepingComputer (@BleepinComputer) May 14, 2020
The FBI detailed that the ProLock attack initially gains access to victim networks through phishing emails, which often deliver Microsoft Word documents.
It has been analyzed that Qakbot interferes with configuring a remote desktop protocol and steals login credentials for systems with single-factor authentication.
#DFIR Another actor uses commodity malware as initial access vector. This time QakBot and rebranded PwndLocker – ProLock. Here is a brief on adversary's TTPs:https://t.co/khK455jrba — Oleg Skulkin (@oskulkin) May 14, 2020
Group-IB stated that the ransomware attacks ask for a total payment of 35 BTC, worth $337,750 as of press time.
Likewise, a Bleeping Computer study shows that ProLock demands an average of $175,000 to $ 660,000 per attack by depending on the size of the targeted network.
Brett Callow, the threat analyst of Emsisoft, explained:
“ProLock is unusual in that it is written in assembly and deployed using Powershell and shellcode. The malicious code is stored in either XML, video, or image files. Notably, the ProLock decryptor supplied by the criminals does not work correctly and corrupted data during the decryption process.”
Callow added that though Emsisoft developed a decryptor to recover victims’ data affected by ProLock without loss, such software does not remove the need for the ransom to be paid as it relies on the key supplied by the criminals.
Though the techniques used by ProLock operators are similar to those of known ransomware groups that filter stolen data like Sodinokibi and Maze, Group-IB clarified:
“Unlike their peers, though, ProLock operators still don’t have a website where they publish exfiltrated data from companies that refuse to pay the ransom.”