HydraCrypt Ransomware

HydraCrypt is a ransomware commonly distributed by the Angler Exploit Kit. It was first detected in early 2016 and part of the CrypBoss Ransomware family. In February 2016, Emisoft released a decrypter for the HydraCrypt and UmbreCrypt ransomware.

Threat ID:: CC-1928
Category:: Ransomware
Threat Severity:: Medium
Threat Vector:
Published:: 11 January 2018 12:00 AM

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Summary

Affected platforms

The following platforms are known to be affected:

Microsoft Windows

Microsoft Windows - All Versions

Threat details

The malware encrypts a user’s files and appends the filenames with the extension “hydracrypt_ID_” suffixed with eight random characters. A plain text file is also dropped with instructions on paying the ransom before the files can be decrypted. The file contains a threat that information may be leaked on dark marketplaces, if the ransom is not paid.

The malware’s impact is more than denying access to sensitive data as at least some data is exfiltrated to a remote host. According to the malware authors, this data could be released if payment is not received, suggesting the malware could also lead to a subsequent compromise in the data’s confidentiality.

A proven decryption software has been released, however, the risk remains moderate due to its use with the Angler Exploit Kit.

The malware initially drops and executes a copy of itself under the folder ChromeSettings2364 in the %AppData% directory, where it is appended with a random name to attempt to evade signature-based detections, and deletes itself. The malware gathers certain information about the target machine and communicates this to a C2 (Command and Control) node.

The ransomware encrypts a wide range of file extensions, excluding .exe, .dll and .sys, with RC4 code. System backups are also encrypted.

Remediation steps

Type	Step
	The first line of defence against new variants of ransomware is user awareness and safe working practices. To avoid becoming infected with Ransomware, ensure that: A robust program of education and awareness training is delivered to users to ensure, they don’t open attachments or follow links within unsolicited emails All operating systems, antivirus and other security products are kept up to date All day to day computer activities such as checking email and browsing the web are performed using non- administrative accounts and that permissions are always assigned on the basis of least privilege Your organisation adopts a holistic all round approach to Cyber Security as advocated by the “10 Steps To Cyber Security” Identifying the source of infection: Identifying the infected machine and unplugging / disconnecting or quarantining it from the network is essential to damage limitation. Users should immediately report infections to their IT support provider, disconnect their network cable, and power the computer down. File auditing should be enabled and file server logs should be monitored to detect signs of unauthorised encryption and allow the source of encryption to be identified (i.e. the infected pc). To limit the damage of ransomware and enable recovery: All critical data must be backed up, and these backups must be sufficiently protected/kept out of reach of ransomware. Multiple backups should be created including at least one off-network backup (e.g. to tape). Recovery: Many of the ransomware variants use common, industry standard encryption algorithms, which makes decryption without the key impossible. The only guaranteed way to recover from a ransomware infection is to restore all affected files from their most recent backup.

Type

Step

The first line of defence against new variants of ransomware is user awareness and safe working practices.

To avoid becoming infected with Ransomware, ensure that:

A robust program of education and awareness training is delivered to users to ensure, they don’t open attachments or follow links within unsolicited emails
All operating systems, antivirus and other security products are kept up to date
All day to day computer activities such as checking email and browsing the web are performed using non- administrative accounts and that permissions are always assigned on the basis of least privilege
Your organisation adopts a holistic all round approach to Cyber Security as advocated by the “10 Steps To Cyber Security”

*Identifying the source of infection: *

Identifying the infected machine and unplugging / disconnecting or quarantining it from the network is essential to damage limitation.
Users should immediately report infections to their IT support provider, disconnect their network cable, and power the computer down.
File auditing should be enabled and file server logs should be monitored to detect signs of unauthorised encryption and allow the source of encryption to be identified (i.e. the infected pc).

To limit the damage of ransomware and enable recovery:

All critical data must be backed up, and these backups must be sufficiently protected/kept out of reach of ransomware.
Multiple backups should be created including at least one off-network backup (e.g. to tape).

Recovery: Many of the ransomware variants use common, industry standard encryption algorithms, which makes decryption without the key impossible. The only guaranteed way to recover from a ransomware infection is to restore all affected files from their most recent backup.

Last edited: 17 February 2020 12:45 pm