Malware

Cheerscrypt

Cheerscrypt is ransomware that was reported in May 2022 as specifically targeting ESXi servers. The available content states that it encrypts data on victim machines using the Sosemanuk stream cipher with a key generated via Elliptic-curve Diffie-Hellman (ECDH). The content identifies it as Cheerscrypt (S1096). No additional high-confidence details on infection vector, associated threat actor, ransom note, file extension, or specific indicators of compromise are provided in the supplied material.

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MITRE ATT&CK

Techniques & procedures

5 distinct techniques documented for this family, organized by ATT&CK tactic.

Execution

1 technique

T1059.012Hypervisor CLIEvidence1

Discovery

2 techniques

T1083File and Directory DiscoveryEvidence2

The content repeatedly describes malware and threat actors listing files and directories, enumerating drives, searching for files by extension/name/path, retrieving file metadata, and browsing file systems (for example: "APT28 has used Forfiles to locate PDF, Excel, and Word documents during collection" and "cmd can be used to find files and directories with native functionality such as dir commands").

T1673Virtual Machine DiscoveryEvidence1

Impact

2 techniques

T1486Data Encrypted for ImpactEvidence3

Numerous ransomware/wiper examples enumerate files before encryption, such as "BlackCat can enumerate files for encryption", "NotPetya searches for files ending with dozens of different file extensions prior to encryption", and "WastedLocker can enumerate files and directories just prior to encryption."

T1489Service StopEvidence1

ACTIVITY FEED

Recent activity

3 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

3 SOURCESView more in app

trend micro researchNews

Feb 20, 2023

Royal Ransomware Expands Attacks by Targeting Linux ESXi Servers

Ransomware referenced as targeting VMware ESXi servers.

mitre attackNews

Jan 23, 2026

Data Encrypted for Impact, Technique T1486 - Enterprise | MITRE ATT&CK®

Ransomware using Sosemanuk stream cipher with ECDH-derived keys.

mitre attackNews

Mar 18, 2026

Data Encrypted for Impact, Technique T1486 - Enterprise | MITRE ATT&CK®

Ransomware using Sosemanuk stream cipher with ECDH-derived keys.

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IOC matching

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Threat actor attribution

Named campaigns wielding this family, with evidence pinned to each claim.

Exploited vulnerabilities

CVEs this family uses for access and lateral movement.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

MITRE ATT&CK mapping5

Every documented technique, ranked by evidence weight.

Researcher chatter

Reddit, Mastodon, and CTI community discussion around this family.

Cheerscrypt