How to remove SynAck ransomware virus

SynAck ransomware is a sophisticated virus that targets businesses all over the world

SynAck (also known as Syn Ack) ransomware^[1] is a crypto-virus that started attacking victims' computers in September 2017. Since then, four variants of this cyber infection appeared. The latest version is quite significant in cybersecurity world, as it is the first ransomware to use Process Doppelgänging technique to infect PCs and evade security software detection. While this process is not completely new (it has been first presented in December 2017 at the BlackHat conference), it is, however, the first time it is used for a ransomware attack.

The purpose of the ransomware is the same as of many other viruses (such as Scarab, GandCrab 3, Dharma, etc.) – to encrypt files and demand ransom for data release. The virus drops a ransom note called RESTORE_INFO-[id].txt on the desktop to explain to users what to do to get files back. SynAck uses ECC-SECP192R1 & AES-ECB-256 encryption algorithms, which makes it impossible to decrypt files unless a unique decryption key is used (hackers store it on a remote server).

Different SynAck virus versions provide slightly different information in the ransom notes. Each version presents contact details so that the victim could get in touch with the criminals:

• The first SynAck version suggests writing to synack@secmail.pro, synack@scryptmail.com, synack@xmail.net, synack@cock.li or synack@countermail.com and leaves BM-2cTp9eosgjWs8SV14kYCDzPN3HJkwYk1LQ BitMessage ID as an alternate way of contacting criminals;
• The second ransomware version provides tyughjvbn13@scryptmail.com email and a different BitMessage ID: BM-2cStoatQC4mDNWDHAoo2C1nYZJXhDsjCLj;
• The third SynAck malware version suggests writing to bubkjdws@scryptmail.com or BM-2cWsgWxq1X5M6qjDEBPvCdEbbPLn2zi43k via BitMessage;
• The latest version, SynAck FES asks victims to email synack@scryptmail.com or synack@countermail.com and offers to contact criminals via BM-2cTp9eosgjWs8SV14kYCDzPN3HJkwYk1LQ via BitMessage, in case there is no reply within 24 hours.

According to victims’ reports, the SynAck developers can ask as much as $2100 in Bitcoin for data recovery service. Unfortunately, the wallet associated with the virus currently holds over 98 Bitcoins, which means that criminals have collected a lot of ransoms already. You shouldn’t pay them – this only motivates them to keep updating and improving their illegal operations.

The virus doesn’t use the same extension to mark victim’s files – instead, it generates an individual set of ten random characters per file and appends it after the original file extension.

It is highly advisable to remove SynAck virus as soon as you notice its presence on your computer. Please remember that removing the virus won’t recover your files – you have to have a data backup in order to do it. However, programs like FortectIntego or SpyHunterCombo Cleaner can not only eliminate the ransomware but also restore corrupted Windows system files that may have been destructed during the cyber attack.

We do not suggest trying to perform manual SynAck removal because the virus is simply too sophisticated to be deleted by inexperienced computer users. Besides, you must check whether the ransomware was the only virus that entered your computer, so a full computer scan is highly recommended.

The newest version of SynAck tries to avoid detection and analysis by using Doppelgänging Process

According to Kaspersky Lab,^[2] The newest version of SynAck uses an intricate technique (Process Doppelgänging) to avoid detection and analysis. This method allows the virus to use NTFS transactions to start a malignant process from the transacted file, making the malicious process look like a genuine one, as well as helping to avoid security software detection.

The virus also prevents automatic sandbox analysts by checking the directory it executes from. SynAck will not proceed if it detects an attempt of launch from “wrong” directory, and exit the process instead.

After infiltration, malware can display a ransom note directly from Windows login screen by modifying LegalNoticeCaption and LegalNoticeText Registry Keys. It states the following:

Hello. Your files are encrypted. To restore files, please contact us by e-mail: synack@scryptmail.com or synack@countermail.com.

An interesting fact about this version of the virus is that it avoids targeting users from Russia, Belarus, Ukraine, Georgia, Tajikistan, Kazakhstan, and Uzbekistan. The malware consists of a hard-coded list of keyboard layouts, which allows it to compare it to the one present on the targeted PC. If one of the layouts matches SynAck's one, the virus simply stays idle for 300 seconds and then calls ExitProcess, avoiding file encryption. Ransomware actively targets users from United States, Kuwait, Germany, and Iran instead.

Users report Syn Ack distribution via RDP configuration

SynAck ransomware seems to be distributed via RDP attacks^[3]. Criminals are trying to brute-force their way into victim’s computers or computer networks. This way, the virus can quickly compromise enterprise networks and demand huge ransoms for data recovery tools.

On top of that, the malware might be distributed using other means such as malvertising, malicious spam, and similar techniques. The continuous movement of Bitcoins in the aforementioned Bitcoin wallet gives us a reason to believe that the malicious software might be provided as ransomware-as-a-service, meaning that any criminal can join the affiliate program and help to distribute the virus further.

Keeping your anti-malware software up-to-date, creating a data backup and enabling automatic software updates is what can help you to prevent a ransomware attack. Do not forget to use powerful passwords on Remote Desktop Connection accounts, too.

Experts report that the described ransomware strongly affected U.S., France, Belgium and Netherlands^[4].

Get rid of SynAck ransomware using security software

It is highly advisable to use professional malware removal software to remove SynAck virus. It is not a typical computer program, and you can’t uninstall it via Control Panel using its uninstaller.

To perform a successful SynAck removal, employ a software like FortectIntego or MalwarebytesMalwarebytes. You might need to restart your PC in a particular mode if the security software fails to start in the normal regime (it means that the malware is trying to block your attempts to identify and remove the virus).