A new ransomware is targeting manufacturing, along with healthcare, technology and education, researchers said.
Defray, found by researchers at Proofpoint, has only been discovered in two attacks so far.
The attack goes out via Word documents attached to phishing emails. The campaigns consisted of only several messages each, while the lures were specifically crafted for the intended targets.
Distribution of Defray has several characteristics:
• Defray is currently being spread via Microsoft Word document attachments in email
• The campaigns are as small as several messages each
• The lures are custom crafted to appeal to the intended set of potential victims
• The recipients are individuals or distribution lists, e.g., group@ and websupport@
• Geographic targeting is in the UK and U.S.
• Vertical targeting varies by campaign and is narrow and selective
The Microsoft Word documents carrying the ransomware contain an embedded OLE packager shell object. When the victim opens the document, the malware is dropped in the %TEMP% folder, and a file named taskmgr.exe or explorer.exe is then executed.
Defray contains a hardcoded list of around 120 file extensions to encrypt, though security researchers from Proofpoint said in a blog post the malware would also encrypt files with extensions that are not on the list (such as .lnk and .exe).
The ransomware doesn’t change the extension of the encrypted files, researchers said.
The threat communicates with the command and control server via HTTP (clear-text) and HTTPS, to send infection information.
After completing the encryption process, the malware disables startup recovery and deletes volume shadow copies. On Windows 7, Defray would also monitor and kill running programs such as the Task Manager and browsers.
To inform the victim of what happened with the files, the ransomware creates a ransom note called FILES.TXT in “many folders throughout the system,” along with a file called HELP.txt on the desktop (with identical content).
“The ransom note […] follows a recent trend of fairly high ransom demands; in this case, $5000. However, the actors do provide email addresses so that victims can potentially negotiate a smaller ransom or ask questions, and even go so far as to recommend BitMessage as an alternative for receiving more timely responses. At the same time, they also recommend that organizations maintain offline backups to prevent future infections,” Proofpoint researchers said.
To date, the malware was observed only in two distinct attacks, one targeting manufacturing and technology on August 15, and another focusedon healthcare and education on August 22.
The emails featured the subject “Order/Quote” and referenced a UK-based aquarium with international locations. In the second campaign, the emails used a UK hospital logo, saying it was from the director of information management and technology at the hospital.