Published: November 27th, 2017
Infosec leaders should be warning employees of opening email with the headers “Scanned from …” one of Canon/Epson/HP/Lexmark because the messages are triggers for a ransomware campaign.
Security vendors Forcepoint and F-Secure said late last week that the messages are part of a massive malicious email campaign from the Necurs botnet pouring out a new strain of ransomware at the rate of over 2 million emails per hour. The main targets are .com top domains, as well as region-specific domains in the United Kingdom, Australia, France, and Germany.
Users are infected by clicking on an attachment formatted as “image2017-11-23-(7 random digits).7z“.
The final payload is the Scarab ransomware, which was first seen last June, whose code is based on the open source “ransomware proof-of-concept” called HiddenTear.
Once installed it encrypt files, adding the extension “.[email@example.com].scarab” to affected files. A ransom note with the filename “IF YOU WANT TO GET ALL YOUR FILES BACK, PLEASE READ THIS.TXT” is dropped within each affected directory. Forcepoint notes the misspelling of “support” is present in both the modified filenames and the ransom note, and is presumably a result of the availability of email addresses on the Protonmail service.
Unusually, Forcepoint said, the note does not specify the amount being demanded, instead simply stating that “the price depends on how fast you write to us”. This note is also automatically opened by the malware after execution.
(Screenshot from F-Secure of ransom note)
The Necurs botnet has been used to distribute the Locky ransomware, the Dridex banking trojan and “pump-and-dump” spam schemes for duping people into buying stock of small companies, which artificially pushes their prices up.
According to IBM’s Security Intelligence blog last April, Necurs has up to six million infected endpoints on the botnet. “Necurs emerged in 2012 as an infector and rootkit, and quickly partnered with elite cybercrime gangs to become part of the top spamming and infection forces in the malware realm,” the column says.
By now many anti-virus/anti-malware solutions have techniques for alerting on this threat, so it helps to keep AV up to date. It also helps to be part of a threat intelligence feed. Security awareness training is also essential to regularly remind staff to not eagerly click on every link in every email. Finally, good protection practice for any ransomware means having detached backup for all systems.