Category Archives: ransomware

BTCWare/Nuclear – don’t pay up!

Bleeping Computer: New Nuclear BTCWare Ransomware Released (Updated)

Lawrence Abrams notes: “Michael Gillespie discovered that the developers of this variant messed up on the encryption of files greater than 10MB in file size and will not be able to decrypt them. It was also discovered that this same behavior was seen with other files of random sizes. Therefore, it is advised that you do not pay the ransom as there is a good chance many of your files not be able to be decrypted.”

David Harley

Heimdal’s Anti-Ransomware Protection Plan

Andra Zaharia, security evangelist at Heimdal, has published a very useful and exhaustive checklist for reducing your exposure to ransomware: The Anti-Ransomware Protection Plan You Need to Follow Today.

I get tired of reading ‘how to defend against ransomware’ articles that miss out vital points like not staying permanently connected to in-the-cloud storage, but this one really does cover most of the angles. Very nice.

David Harley

SyncCrypt: Getting the Ransomware Picture?

Lawrence Abrams, for Bleeping Computer, describes how the SyncCrypt Ransomware Hides Inside JPG Files, Appends .KK Extension.

The article describes ransomware discovered by EmsiSoft’s xXToffeeXx, distributed as spam attachments containing WSF (Windows Script File) objects. The WSF script pulls down images containing embedded Zip files. Abrams reports that the ‘WSF attachments are pretending to be court orders with file names like CourtOrder_845493809.wsf.’

VirusTotal searches today indicate that detection is rising of the image file for which a hash is provided, but still lower than the detection rate for the executable, which the majority of mainstream security products now detect. The JPGs are not directly harmful, but the embedded Zip file contains the malicious sync.exe executable. Detection of the WSF file for which a hash is provided is also lower than for the executable.

There’s no free decryption for affected data at this time.

IOCs, filenames etc. are appended to the Bleeping Computer analysis.

David Harley

 

Cerber now kind to canaries

Cybereason: Researchers at Cybereason have discovered a new strain of the Cerber ransomware that implements a new feature to avoid triggering canary files.

Apparently this strain of Cerber assumes that any malformed image file is a ‘canary’ file (a variation on the old idea of a goat file) and avoids encrypting it or any other file in the directory in which it’s found.

A goat file can be used to facilitate detection and/or analysis of a virus when it has been infected, by analogy with a ‘sacrificial goat’.

A canary file is intended to act like ‘a canary in a coal mine’, giving early warning of an attempt by ransomware to encrypt files, by analogy with a canary dropping unconscious or dead at the first hint of dangerous gases such as carbon monoxide.

Since it’s rather easy to generate a ‘malformed image file’, it’s been suggested that people do so to help protect folders containing valuable files. I suspect, however, that the Cerber gang (and other malefactors) have already twigged that one, so I certainly wouldn’t rely on such a strategy.

David Harley

Ransomware targeting WordPress sites

WordFence, which offers a security plugin for WordPress sites, reports on Ransomware Targeting WordPress – An Emerging Threat, claiming to have ‘captured several attempts to upload ransomware that provides an attacker with the ability to encrypt a WordPress website’s files and then extort money from the site owner.’

I hope the company won’t mind my quoting this important paragraph:

If you are affected by this ransomware, do not pay the ransom, as it is unlikely the attacker will actually decrypt your files for you. If they provide you with a key, you will need an experienced PHP developer to help you fix their broken code in order to use the key and reverse the encryption.

Commentary by HelpNet Security here: EV ransomware is targeting WordPress sites

David Harley