Ryuk
Ryuk is a ransomware family first discovered in 2018. The provided content describes it as a well-known ransomware used in intrusions against organizations including hospitals and other enterprises, and notes FBI-attributed activity installing Ryuk on servers and workstations between March 2019 and September 2020. Ryuk is repeatedly linked to the TrickBot malware operation and distribution ecosystem, and multiple references state that Conti emerged from the Ryuk group or cybercrime syndicate. The content also associates Ryuk with Wizard Spider and notes broader links to Russia-based cybercrime.
Behaviorally, the content states that Ryuk performs pre-encryption tradecraft including service and process termination, including stopping services related to anti-virus and using a kill.bat script prior to encryption. It has been observed to query the registry key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Nls\Language and the InstallLanguage value, and to stop execution if the system language corresponds to Russian (0x419), Ukrainian (0x422), or Belarusian (0x423). The content further states that Ryuk deletes recovery artifacts using vssadmin Delete Shadows /all /quiet and vssadmin resize shadowstorage to force deletion of shadow copies created by third-party applications. It has also been observed injecting itself into remote processes to encrypt files using VirtualAlloc, WriteProcessMemory, and CreateRemoteThread.
Infection and delivery relationships mentioned in the content include reliance on the TrickBot distribution system and benefit from EMOTET loader activity; other reporting cited in the content also ties BazarCall campaigns historically to Ryuk and Conti operations. The content references reconnaissance activity seen in Ryuk intrusions, including suspicious use of net.exe or net1.exe for group and account enumeration. Overall, the supplied material characterizes Ryuk as an enterprise-targeting ransomware family closely tied to TrickBot-era cybercrime operations and as a predecessor to Conti.
Hunt this family in your stack
Mallory pivots from this family to the IOCs, detections, and named campaigns that touch your stack, and pages you when something new lands.
Vulnerabilities exploited
1 CVE Mallory has correlated with this family across public research and vendor advisories. Each row links to the full Mallory page for that vulnerability.
"Privileges have been escalated using Mimikatz, Rubeus4 [13], or by exploiting a Zerologon vulnerability (CVE-2020-1472) [26]."
Groups observed using it
12 distinct threat actors attributed by public researchers. Open in Mallory to see the full evidence chain and overlapping campaigns.
Example 8 — Pivot from malware to infrastructure You found a Ryuk ransomware sample (SHA256 hash).
The Conti ransomware, or malware, first appeared in December 2019, and some security sources said it appeared to be the successor of Ryuk ransomware, which first surfaced around the middle of 2018. Ryuk originated in Russia, and appears to be controlled by a cyber crime gang known as Russian Spider.
The Conti ransomware, or malware, first appeared in December 2019, and some security sources said it appeared to be the successor of Ryuk ransomware, which first surfaced around the middle of 2018. Ryuk originated in Russia, and appears to be controlled by a cyber crime gang known as Russian Spider.
"...gain initial access to corporate networks for Ryuk, and later, Conti ransomware attacks."
"BazaLoader... subsequently installed a ransomware strain called Ryuk."
"The operators of Ryuk ransomware are at it again... There was speculation that the Ryuk actors had moved on to a rebranded version of the ransomware, called Conti."
Techniques & procedures
32 distinct techniques documented for this family, organized by ATT&CK tactic.
Resource Development
2 techniques
Resource Development
Initial Access
1 technique
Initial Access
Execution
4 techniques
Execution
Batch script that uses WMIC to execute a BITSAdmin transfer of a payload ransomware to each targeted machine in the comps<##>.txt files.
During the 2022 Ukraine Electric Power Attack, Sandworm Team leveraged Scheduled Tasks through a Group Policy Object (GPO) to execute CaddyWiper at a predetermined time.
During the 2016 Ukraine Electric Power Attack, Sandworm Team used the xp_cmdshell command in MS-SQL. During the 2025 Poland Wiper Attacks, the adversaries leveraged PsExec to run cmd.exe commands on multiple victim machines. Numerous malware families and groups are described as using cmd.exe, cmd /c, Windows command shell, or command-line interfaces to execute commands, payloads, reconnaissance, persistence, cleanup, and ransomware actions.
Persistence
5 techniques
Persistence
During the 2022 Ukraine Electric Power Attack, Sandworm Team leveraged Scheduled Tasks through a Group Policy Object (GPO) to execute CaddyWiper at a predetermined time.
Across the content, malware repeatedly 'adds Registry Run keys', 'creates Registry entries', 'modifies the Windows Registry', or 'overwrites registry keys' to maintain persistence.
Batch script that uses WMIC to execute a BITSAdmin transfer of a payload ransomware to each targeted machine in the comps<##>.txt files.
Examples include 'adds Registry Run keys to establish persistence', 'creates a shortcut in the Startup folder', and 'RunOnce Registry key to run itself on safe mode.'
The content repeatedly describes malware and threat actors establishing persistence by adding values under HKCU/HKLM\Software\Microsoft\Windows\CurrentVersion\Run or RunOnce, and by placing executables, scripts, .lnk files, or .bat files in the Windows Startup folder.
Privilege Escalation
7 techniques
Privilege Escalation
During the 2022 Ukraine Electric Power Attack, Sandworm Team leveraged Scheduled Tasks through a Group Policy Object (GPO) to execute CaddyWiper at a predetermined time.
The content repeatedly describes malware and threat actors injecting shellcode, DLLs, or payloads into legitimate processes such as svchost.exe, explorer.exe, iexplore.exe, cmd.exe, lsass.exe, and browser processes.
ROKRAT can use VirtualAlloc, WriteProcessMemory, and then CreateRemoteThread to execute shellcode within the address space of Notepad.exe. Ryuk has injected itself into remote processes to encrypt files using a combination of VirtualAlloc, WriteProcessMemory, and CreateRemoteThread.
ROKRAT can use VirtualAlloc, WriteProcessMemory, and then CreateRemoteThread to execute shellcode within the address space of Notepad.exe. Ryuk has injected itself into remote processes to encrypt files using a combination of VirtualAlloc, WriteProcessMemory, and CreateRemoteThread. Woody RAT can inject code into a targeted process by writing to the remote memory of an infected system and then create a remote thread.
In at least one incident, FIN12 used GPOs, scheduled tasks, and WebDAV to execute a RYUK payload hosted on a network file share.
Examples include 'adds Registry Run keys to establish persistence', 'creates a shortcut in the Startup folder', and 'RunOnce Registry key to run itself on safe mode.'
The content repeatedly describes malware and threat actors establishing persistence by adding values under HKCU/HKLM\Software\Microsoft\Windows\CurrentVersion\Run or RunOnce, and by placing executables, scripts, .lnk files, or .bat files in the Windows Startup folder.
Stealth
7 techniques
Stealth
The content repeatedly describes malware and threat actors using obfuscated code, encrypted strings, Base64/XOR/RC4/AES encoding, VMProtect/ConfuserEx/SmartAssembly, stack strings, control-flow flattening, opaque predicates, and hidden payloads to evade analysis and detection.
Since at least February 2020, FIN12 has leveraged a series of in-memory droppers including, MALTSHAKE, ICECANDLE, WHITEDAGGER, WEIRDLOOP, and templates associated with Cobalt Strike's Artifact Kit to deploy various malware payloads.
During the 2016 Ukraine Electric Power Attack, DLLs and EXEs with filenames associated with common electric power sector protocols were used to masquerade files.
The content repeatedly describes malware and threat actors injecting shellcode, DLLs, or payloads into legitimate processes such as svchost.exe, explorer.exe, iexplore.exe, cmd.exe, lsass.exe, and browser processes.
ROKRAT can use VirtualAlloc, WriteProcessMemory, and then CreateRemoteThread to execute shellcode within the address space of Notepad.exe. Ryuk has injected itself into remote processes to encrypt files using a combination of VirtualAlloc, WriteProcessMemory, and CreateRemoteThread.
ROKRAT can use VirtualAlloc, WriteProcessMemory, and then CreateRemoteThread to execute shellcode within the address space of Notepad.exe. Ryuk has injected itself into remote processes to encrypt files using a combination of VirtualAlloc, WriteProcessMemory, and CreateRemoteThread. Woody RAT can inject code into a targeted process by writing to the remote memory of an infected system and then create a remote thread.
Defense Impairment
3 techniques
Defense Impairment
Across the content, malware repeatedly 'adds Registry Run keys', 'creates Registry entries', 'modifies the Windows Registry', or 'overwrites registry keys' to maintain persistence.
Discovery
6 techniques
Discovery
The content repeatedly describes malware and threat actors using commands and APIs such as ipconfig /all, ifconfig, arp -a, route print, nbtstat, netsh, GetAdaptersInfo, and GetIpNetTable to gather IP addresses, MAC addresses, DNS, DHCP, gateways, routing tables, ARP cache, proxy settings, domains, and network adapter/interface details.
The content repeatedly describes malware and threat actors obtaining lists of running processes, using utilities such as tasklist, ps, WMI, Get-Process, CreateToolhelp32Snapshot, EnumProcesses, and similar APIs/commands to enumerate active processes on victim systems.
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").
title: Suspicious Group And Account Reconnaissance Activity Using Net.EXE ... Detects suspicious reconnaissance command line activity on Windows systems using Net.EXE ... tags: - attack.discovery - attack.t1087.001 - attack.t1087.002
selection_accounts_root: CommandLine|contains: ' accounts ' ... selection_accounts_flags: CommandLine|contains: ' /do' # short for domain ... tags: - attack.discovery - attack.t1087.001 - attack.t1087.002
Avaddon checks for specific keyboard layouts and OS languages to avoid targeting Commonwealth of Independent States (CIS) entities... Bazar can perform a check to ensure that the operating system's keyboard and language settings are not set to Russian... Clop has checked the keyboard language using the GetKeyboardLayout() function... Ryuk has been observed to query the registry key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Nls\Language and the value InstallLanguage.
Lateral Movement
3 techniques
Lateral Movement
During Operation CuckooBees, the threat actors used scheduled tasks to execute batch scripts for lateral movement with the following command: SCHTASKS /Create /S <IP Address> /U <Username> /p <Password> /SC ONCE /TN test /TR <Path to a Batch File> /ST <Time> /RU SYSTEM.
Collection
1 technique
Collection
Command and Control
1 technique
Command and Control
Impact
2 techniques
Impact
IOCs tracked for this family
134 indicators attributed across vendor reports, sandbox runs, and researcher write-ups. Full values are available in Mallory.
IPs, domains, and DNS infrastructure linked to this family.
Recent activity
162 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
Ransomware sample used as an example for pivoting from malware to related infrastructure, campaigns, and ATT&CK techniques such as T1486 and T1490.
Ransomware family explicitly mentioned as associated with TrickBot.
Referenced as the predecessor gang from which Conti emerged.
A ransomware/cybercrime group from which the Conti operation emerged, indicating lineage between Ryuk and Conti.
The version that knows your environment.
Match every observed IP, domain, and hash against your live telemetry.
Named campaigns wielding this family, with evidence pinned to each claim.
CVEs this family uses for access and lateral movement.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Every documented technique, ranked by evidence weight.
Reddit, Mastodon, and CTI community discussion around this family.