BitPaymer Ransomware

tPaymer, also known as WPEncrypt, is a relatively new ransomware variant that first appeared in mid-2017.

Threat ID:: CC-1609
Category:: Ransomware
Threat Severity:: Medium
Threat Vector:: Email spam, Insecure network, Exploit
Published:: 29 August 2017 12:00 AM

Report a cyber attack: call 0300 303 5222 or email [email protected]

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Summary

tPaymer, also known as WPEncrypt, is a relatively new ransomware variant that first appeared in mid-2017.

Affected platforms

The following platforms are known to be affected:

Microsoft Windows

Microsoft Windows - All versions

Threat details

The malware is believed to primarily be delivered via insecure RDP connections and network compromise.

Attackers perform brute-force attacks on internet exposed RDP endpoints, when a weak password is discovered and access to one system is gained the attackers attempt to move latterly on the breached network and install Bit Paymer manually on each compromised system.

Other intelligence suggests BitPaymer may also be delivered via spam emails, malicious advertisements and via PUPs potentially unwanted programs.

There does not appear to be any widespread campaigns that are distributing this malware, indicating that attacks may be more targeted in nature when compared with other variants that are spread in large-scale, mass campaigns.

The ransomware appends the ".locked" string at the end of each encrypted file name.
BitPaymer also generates text files "readme_txt" holding the ransom note and drops them all over the filesystem, where it encrypted files.

The ransom note instructs victims to connect to a Tor-based portal where victims can pay (in Bitcoin) to obtain decryption software and a private key to enable file recovery "for every single infected computer in your network".

BitPaymer asks victims to pay a significant ransom demand totalling 50 Bitcoins in two stages. Victims are initially asked to pay 1 Bitcoin to verify they have paid the correct account before be asked to pay the remainder.

The ransomware encrypts files with a combination of RC4 and RSA-1024 encryption algorithms

Remediation steps

Type

Step

If Remote Desktop Protocol (RDP) is not used, then ensure port 3389 (TCP/UDP) is blocked at your internet firewall. If RDP is used, then:

Only allow access for authorised RDP users.
Enforce strong password policies.
Enforce multi-factor authentication.
Don't allow RDP access for privileged user accounts.
Don’t use generic accounts.
Set user accounts with an expiry date.
Audit user accounts periodically.
Only allow point-to-point connections from specific IP addresses where feasible.
Ensure Transport Layer Security (TLS) is up-to-date.
Log and monitor all RDP activity and investigate unusual behaviour.
Consider only allowing RDP for authorised virtual private network (VPN) connections.

If a device on your network becomes infected with ransomware it will begin encrypting local machine files and files on any network the logged-in user has permission to access. For system administration accounts this may include backup storage locations.

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, anti-virus and other security products are kept up to date.
All day to day computer activities such as email and internet are performed using non-administrative accounts and that permissions are always assigned based on the principle 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 affected device and 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 device).

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).

The only guaranteed way to recover from a ransomware infection is to restore all affected files from their most recent backup.

If Remote Desktop Protocol (RDP) is not used, then ensure port 3389 (TCP/UDP) is blocked at your internet firewall. If RDP is used, then:

* Only allow access for authorised RDP users.

* Enforce strong password policies.

* Enforce [multi-factor authentication|/cyber-alerts/2019/Two+Factor+Authentication+-+2FA].

* Don't allow RDP access for privileged user accounts.

* Don’t use generic accounts.

* Set user accounts with an expiry date.

* Audit user accounts periodically.

* Only allow point-to-point connections from specific [IP addresses|/services/data-security-centre/cyber-security-glossary#ip-address] where feasible.

* Ensure [Transport Layer Security|/services/data-security-centre/cyber-security-glossary#transport-layer-security] (TLS) is up-to-date.

* Log and monitor all RDP activity and investigate unusual behaviour.

* Consider only allowing RDP for authorised [virtual private network|/services/data-security-centre/cyber-security-glossary#virtual-private-network] (VPN) connections.

Last edited: 17 February 2020 11:27 am