Learn how to go about the predicament where files on a computer become encrypted and get appended with the .wallet extension due to a ransomware attack.
What is .wallet file ransomware? (May 2017)
It makes sense to provide a brief retrospective insight into the subject matter of this article first. Breaking news hit the headlines of security resources mid-November 2016: the developers of the prolific CrySiS ransomware released the master decryption keys for their perpetrating software. This seemed like a big win for everyone infected back then. However, the criminals’ craft has had an adverse continuation: unidentified threat actors have revived the code of the defunct threat and created a new crypto infection dubbed Dharma. Having contaminated a Windows machine, the malicious newbie encrypts most of the victim’s personal files and appends the .[attacker_email].wallet or .[attacker_email].dharma extension to each one. The email addresses used in this filename skewing pattern may include:
Consequently, if a file was named sample.pdf before the compromise, it turns into sample.pdf.[email@example.com].wallet or sample.pdf.[firstname.lastname@example.org].dharma after the ransomware has encrypted it. Again, the email address may vary. Some victims are reporting the .zzzzz extension as well, which is the same as the one used by one of the previous Locky ransomware variants. The file renaming format is different than the one utilized by Locky, though, where the extension is prepended with a random 32-character string. The Dharma offending program also drops ransom instructions called README.txt and README.jpg on the desktop and inside individual directories with scrambled data.
Whereas the CrySiS/Dharma ransomware pioneered in using the .wallet extension as a way to label hostage data entries, this indicator of compromise has since gained popularity with developers of other strains as well. In late March 2017, the Sanctions ransomware started making the rounds, staining encrypted items with this particular suffix. Similarly, the newest variant of the CryptoMix infection active as of May 2017 followed suit. This trend of overlapping use cases has called forth a great deal of ambiguity regarding ransomware identification, making it more difficult to work out which specific .wallet extension ransomware breed a victim is facing.
As far as the current CryptoMix campaign goes, the ransom notes are called #_RESTORING_FILES_#.txt, and the full extension format is as follows: .[email token].ID[16-character victim ID].wallet. The list of possible email addresses includes email@example.com, firstname.lastname@example.org, and email@example.com. These are informative clues for determining the strain. Fortunately, the conventional data recovery mechanisms apply to all samples regardless.
Ultimately, the decryption process revolves around contacting the attackers via the email address indicated in the extension of every locked entry, or in the help file dropped by the infection. The size of the ransom reportedly depends on the number of infected computers. If the ransomware hits an organization’s network, the crooks may demand up to 7 BTC, which is about 5,000 USD. The average amount per computer is 2 BTC and it tends to increase as the time goes by. Some infected users have been able to negotiate the terms of recovery and get the price reduced considerably. Essentially, successful decryption is a function of the availability of a high-entropy private key, which is unique to every incident.
The .wallet (.dharma, .zzzzz) files virus proliferates by means of exploits and phishing. The former technique is only efficient if a targeted user has been neglecting critical software updates. Having browsed to a hacked website, they run the risk of being redirected to an exploit’s landing page, which takes advantage of unpatched programs’ vulnerabilities and executes the ransomware. The latter, phishing, methodology requires users’ manual action. More specifically, they trigger the contamination chain by opening a malicious attachment disguised as an invoice, payroll, CV or job offer. Unfortunately, there is no universal free decryption tool for .wallet files ciphered by the Dharma or CryptoMix virus. In some cases, though, the techniques below may be of help.
.Wallet ransomware automated removal and data recovery
Owing to an up-to-date database of malware signatures and intelligent behavioral detection, the recommended software can quickly locate the infection, eradicate it and remediate all harmful changes. So go ahead and do the following:
1. Download and install the antimalware tool. Open the solution and have it check your PC for PUPs and other types of malicious software by clicking the Start Computer Scan button
2. Rest assured the scan report will list all items that may harm your operating system. Select the detected entries and click Fix Threats to get the troubleshooting completed.
Data recovery toolkit to the rescue
Some strains of ransomware delete the original files after the encryption routine has been completed. As hostile as this activity appears, it can play into your hands. There are applications designed to revive the information that was obliterated because of malfunctioning hardware or due to accidental removal. The tool called Data Recovery Pro by ParetoLogic features this type of capability therefore it can be applied in ransom attack scenarios to at least get the most important files back. So download and install the program, run a scan and let it do its job.
.wallet ransomware manual removal and file recovery
Some ransomware strains terminate themselves after completing the encryption job on a computer, but some don’t. Furthermore, the Locky virus may prevent victims from using popular antimalware tools in order to stay on board for as long as possible. Under the circumstances, it may be necessary to utilize the Safe Mode with Networking or System Restore functionality.
- Restart the machine. When the system begins loading back up, keep pressing the F8 key with short intervals. The Windows Advanced Options Menu (Advanced Boot Options) screen will appear.
- Use arrow keys to select Safe Mode with Networking and hit Enter. Log on with the user account infected by the ransomware.
- Click on the Search icon next to the Start menu button. Type msconfig in the search field and select the System Configuration option in the results. Go to the Boot tab in the upper part of the GUI.
- Under Boot options, select Safe boot and click the Apply button. A prompt will appear to reboot the computer so that the changes take effect. Select the Restart option and wait for the system to load into Safe Mode. Again, log on with the ransomware-stricken user account.
In Safe Mode, the ransom Trojan won’t keep security software from running or otherwise thwart troubleshooting. Open your preferred web browser, download and install an antimalware tool of choice and start a full system scan. Have all the detected ransomware components removed in a hassle-free way..
- Open Windows Advanced Options Menu as described in the previous section: hit F8 repeatedly when the PC is starting up. Use arrow keys to highlight the Safe Mode with Command Prompt entry. Hit Enter.
- In the Command Prompt window, type cd restore and hit Enter
- Type rstrui.exe in the new command line and press Enter
- When the System Restore screen pops up, click Next, select a restore point that predates the contamination, and use the application’s controls to roll back the system to this earlier state.
Be advised that even after the ransomware is removed, files will still be encrypted and inaccessible. The malicious code cleanup part, however, is important because it keeps a relapse of the infection from occurring further on and eliminates all opportunistic malware.
Checking one’s options regarding this workaround is doable in two ways: through the Properties menu of each file or by means of the remarkable open-source tool called Shadow Explorer. We recommend the software-based way because it’s automated, hence faster and easier. Just install the app and use its intuitive controls to get previous versions of the encrypted objects reinstated.
Alternatively, you can leverage the Previous Versions feature, which is native to Windows operating system. This method is more cumbersome that the use of ShadowExplorer, but it can help restore the most important individual files on condition that the ransomware failed to disable the Volume Snapshot Service on the computer. Right-click on a file of choice and select Properties. Then, go to the Previous Versions tab as illustrated below.
Go ahead and pick the file’s latest backup version on the list. Use the Copy or Restore buttons to reinstate this object to a new path or to its original folder, respectively.
- Toggle your email provider’s anti-spam settings to filter out all the potentially harmful incoming messages. Raising the bar beyond the default protection is an important countermeasure for ransom Trojans.
- Define specific file extension restrictions in your email system. Make sure that attachments with the following extensions are blacklisted: .js, .vbs, .docm, .hta, .exe, .cmd, .scr, and .bat. Also, treat ZIP archives in received messages with extreme caution.
- Rename the vssadmin.exe process so that ransomware is unable to obliterate all Shadow Volume Copies of your files in one shot.
- Keep your Firewall active at all times. It can prevent crypto ransomware from communicating with its C&C server. This way, the threat won’t be able to obtain cryptographic keys and lock your files.
- Back up your files regularly, at least the most important ones. This recommendation is self-explanatory. A ransomware attack isn’t an issue as long as you keep unaffected copies of your data in a safe place.
- Use an effective antimalware suite. There are security tools that identify ransomware-specific behavior and block the infection before it can do any harm.
These techniques are certainly not a cure-all, but they will add an extra layer of ransomware protection to your security setup.
Revise your security status
Post-factum assessment of the accuracy component in malware removal scenarios is a great habit that prevents the comeback of harmful code or replication of its unattended fractions. Make sure you are good to go by running an additional safety checkup.
- Petya ransomware removal and system recovery (upd. June 27)
- Sorebrect ransomware – fileless malware exploits PsExec utility
- Remove MOLE02 ransomware virus and decrypt .mole02 files (upd. June 15)
- Erebus ransomware infects Linux web servers in South Korea
- Decrypt .master ransomware files – BTCWare virus variant