Security firm FireEye says that ransomware variants made up over 70 percent of all malware that its products detected in March.
In October last year ransomware made up well under five percent of malware that FireEye detected, and since then ransomware has climbed steadily as a proportion of overall malware its product installations detect.
Ransomware only breached 10 percent in February 2016, however in March ransomware detections spiked, exceeding 70 percent of the total, according to FireEye.
The rise coincides with numerous security firms detecting a surge in Locky ransomware, which was being spread in March via downloaders embedded in spam email attachments. The attachments purported to contain an invoice or image and later included ZIP files. One of the key methods of infecting targets in the Locky campaign was to trick targets into enabling macros for Office documents.
The VBA modules appeared to be legitimate SQL programs, however Microsoft found that a macro in one of the seven modules was designed to decrypt an encrypted string in another module. Once decrypted, that string turned out to be a URL, from where it would download Locky.
“The VBA project (and, therefore, the macro) will automatically run if the user enables macros when opening the file,” noted Microsoft threat researchers Marianne Mallen and Wei Li.
“Our strongest suggestion for the prevention of Office-targeting macro-based malware is to only enable macros if you wrote the macro yourself, or completely trust and know the person who wrote it,” they added.
FireEye’s new warning about the surge in ransomware follows an alert from the FBI in April over file-encrypting ransomware. The FBI didn’t offer any statistics but said it had received reports of ransomware affecting home PCs, hospitals, school districts, state and local governments, law enforcement agencies, small businesses, and large businesses.
Countering reports that the FBI had suggested paying ransomware demands, the bureau stressed that it does not support paying the ransom since paying up does not guarantee receipt of the decryption key, and encourages ransomware attackers.
Regardless of the FBI’s advice, it was widely reported in February that Hollywood Presbyterian Medical Centre paid around $17,000 in Bitcoin after some computers on its network were infected with file-encrypting ransomware.
The hospital’s CEO said paying to obtain the decryption key was the “most efficient way to restore our systems and administrative functions”.
Lucky however was not the most prevalent piece of ransomware in the first quarter of 2016, according to security firm Kaspersky. According to it, in that period Teslacrypt was the most widely encountered by Kaspersky installations, followed by CTB-Locker, Cryptowall, Cryakl, Scatter, and Rakhni. Locky was in seventh spot. Still, as Kaspersky highlighted, Locky was the “biggest crypto epidemic” in the first quarter of 2016, due to how widely it had been spread across different countries.
FireEye reported in March that it detected Locky infection attempts among its users in 50 nations.
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