The open-source ransomware Hidden Tear continues to spawn more variants, and entries from other ransomware families also appeared this week. One variant describes itself as a “kind” ransomware, an MSIL-compiled ransomware displays a colorful Comic Sans ransom note, while the other, a newly-discovered variant, claims to be able to challenge Windows protection.
BrainLag and Oxar
BrainLag (detected by Trend Micro as Ransom_HiddenTearLag.A) is a variant of the Hidden Tear open-source project that uses the AES algorithm to encrypt files in the following Windows 7 directories: ‘\Public’, ‘\Desktop’, ‘\Contacts’, ‘\Documents’, ‘\Downloads’, ‘\Pictures’, ‘\Music’, ‘\OneDrive’, ‘\Saved Games’, ‘\Favorites’, ‘\Searches’, ‘\Videos’, and ‘\Links.’
BrainLag notably has a simple but stylish black and white lock screen, with a Grim Reaper graphic located in the upper right corner. It also has ‘Infected By BrainLag’ and ‘Venao – 2017’ written on it.
Figure 1. BrainLag lock screen
The Oxarransomware (Ransom_HiddenTearOXAR.A) is another Hidden Tear variant that adds the .OXR file extension to files it encrypts. The variant's ransom note outlines three steps for affected users to follow to get their files back. The first step is to follow a link that will allow the victim to create a Bitcoin (BTC) wallet, followed by an instruction to buy US$100 worth of BTC. The last step involves sending the ransom payment to the specified URL.
Figure 2. Oxar ransom note
Ransed (Ransom_RANSED.A) is an MSIL-compiled ransomware variant that arrives in the system as an Win32.exe file. The ransomware connects to a MySQL server to store victims’ data. It encrypts a variety of file types that include Microsoft Office documents, as well as audio and video file formats.
Its ransom note, which is written in colorful Comic Sans font, demands a ransom of $25 in BTC to recover the encrypted files.
Figure 3. Ransed ransom note
Blackout (Ransom_FANTOMCRYPT.F117GJ) is a newly-discovered ransomware that claims to be a free open-source software in its ransom note. The variant was supposedly designed to test the protection of Windows OS.
Blackout encrypts files using the AES encryption algorithm and could be set to erase all the Shadow Volume Copies from the hard drive with the ‘vssadmin.exe delete shadows /all /Quiet’ command.
Figure 4. Blackout ransom note
Describing itself as a "kind ransomware" that will not delete files, Purge (Ransom_STUPURGE.A) demands a ransom of US$250 for a decrypt key. If by kindness, it meant easily decrypting files using an already available unlock code, which is ‘TotallyNotStupid’, then the irony will be lost.
First detected early this year, the re-emerging Fakeglobe ransomware (RANSOM_FAKEGLOBE.F117BE) appends the .crypt extension to affected files using the AES encryption algorithm. It is distributed through spam emails posing as legitimate invoices or automated responses.
In exchange for a decryptor and how-to guidelines, Fakeglobe demands victims to send a screenshot of their 0.5 BTC payment to an email address indicated on the lock screen.
Figure 6. Fakeglobe ransom note
A multi-layered approach is key to defending all possible gateways from threats like ransomware. IT administrators should not turn a blind eye on keeping employees aware and educated of these varying attack tactics. On the other hand, a solid back-up of important files can mitigate possible damages caused by a ransomware infection.
For small businesses, Trend Micro Worry-Free Services Advanced offers cloud-based email gateway security through Hosted Email Security. Its endpoint protection also delivers several capabilities such as behavior monitoring and real-time web reputation in order detect and block ransomware.
For home users, Trend Micro Security 10 provides strong protection against ransomware by blocking malicious websites, emails, and files associated with this threat.