‘CryWiper’ trojan disguises as ransomware, says Kaspersky

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A new wiper trojan, disguised as a ransomware payload, has been found in the wild by scientists, raising inquiries about the purpose for its existence and the identity of its operators.

CryWiper, named for the distinctive ‘.cry’ extension which it appends on to data files, appears on to start with effect to be a new ransomware strain. Victims’ devices are seemingly encrypted and a ransom notice is left demanding money be sent to a bitcoin wallet tackle. However, the data files are basically corrupted outside of restoration.

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Kaspersky scientists laid out conclusions that establish the malware is really a wiper that corrupts all but the most critical system information, overwriting just about every with facts manufactured by means of a pseudo-random quantity generator.  

The moment on a victim’s process, CryWiper sends the identify of the victim’s machine to a command and command (C2) server, waiting for an activation command to start an attack.

This follows a comparable methodology to ransomware, with features carried out together with the deletion of quantity shadow duplicate to protect against documents from remaining restored and scheduling itself in Windows Undertaking Scheduler to make sure that it restarts just about every five minutes.

CryWiper also ceases MS SQL, MySQL, MS Lively Listing, and MS Trade products and services, so that information related with them are not prevented from getting corrupted.

Scientists pointed out that it disables connection to contaminated equipment as a result of remote desktop protocol (RDP) too, and posited that this is to frustrate the endeavours of security groups responding to the incident.

This marks a divergence from normal ransomware behaviour, as payloads commonly preserve RDP accessibility in purchase to aid lateral attacks throughout networks.

A wiper is a malware pressure built to damage units indiscriminately, or normally trigger chaos and destruction on a victim’s machine. Wipers have been extensively made use of in Russia’s cyber war against Ukraine, and sort aspect of a malware arsenal that has shaped the spine of the escalating threat versus critical nationwide infrastructure (CNI).

An email handle offered in the ransom text file has been in use considering that 2017, linking it to a number of previous ransomware family members. No conclusive identification has however been manufactured linking any of the teams.

In a Russian-language blog put up unpacking the complex facts of the malware, Kaspersky researchers drew even more similarities amongst CryWiper and an additional wiper observed attacking general public infrastructure in Ukraine earlier this calendar year, identified as IsaacWiper.

The two wipers use the exact same pseudo-random generator, ‘Mersenne Vortex’, and are the only two to do so because of to the relative complexity of the algorithm in comparison to other choices.

“It’s not common exercise, nevertheless, deploying damaging payloads that comprise ransom notes, with no intention to acquire a ransom has been witnessed ahead of,” mentioned Andy Norton, European cyber risk officer at Armis.

“NotPetya is an case in point of a former wiper attack. Plausible deniability is a single purpose to increase phony flags to malware payloads, another tactic is to invent fictitious danger actor teams, these kinds of as the ‘Cutting Sword of Justice’ once more with the reason to deflect attribution of the attack.”

At the time of writing, Kaspersky has only observed targeted CryWiper attacks within just the Russian Federation. Offered the mysterious character of the team driving CryWiper, as properly as the strategic intent of the trojan at this phase, firms need to remain alert to the telltale indications of the payload.

To stay away from compromise, Kaspersky recommends near oversight of remote network connections, the use of VPN tunnels for RDP entry, as very well as powerful fairly than popular passwords, and two-factor authentication (2FA) wherever feasible.