S-Type is a Windows malware family associated with espionage-style post-compromise activity. It communicates with command-and-control infrastructure over HTTP, primarily using port 80 with fallback to ports 443 or 8080, and encodes command-and-control traffic with Base64. Observed behavior includes uploading data and files from compromised hosts, indicating use of the established command-and-control channel for exfiltration.
On infected systems, S-Type performs host and user-context reconnaissance. It has been observed checking the privilege level of the compromised user, attempting to determine whether the system uses a Japanese keyboard via the GetKeyboardType API, and executing built-in Windows commands such as net start and net user to enumerate services and account information.
For persistence, S-Type can copy itself under the name of a legitimate Windows component and establish autorun through both Startup-folder shortcut creation and a Registry Run entry. It has also used masquerading by adopting the name of a legitimate Microsoft binary. Additional behavior includes creation of a temporary local user account on the victim system. Some samples have been packed with UPX. Overall, S-Type exhibits characteristics of a backdoor used for persistence, reconnaissance, command-and-control, and data theft on Windows hosts.
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18 distinct techniques documented for this family, organized by ATT&CK tactic.
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.
C:\Users\[Username]\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup C:\ProgramData\Microsoft\Windows\Start Menu\Programs\StartUp HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\User Shell Folders HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders
The content repeatedly describes malware and threat actors establishing persistence by adding values under Registry Run keys such as HKCU\Software\Microsoft\Windows\CurrentVersion\Run and HKLM\Software\Microsoft\Windows\CurrentVersion\Run, and by placing shortcuts or files in Startup folders.
C:\Users\[Username]\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup C:\ProgramData\Microsoft\Windows\Start Menu\Programs\StartUp HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\User Shell Folders HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders
The content repeatedly describes malware and threat actors establishing persistence by adding values under Registry Run keys such as HKCU\Software\Microsoft\Windows\CurrentVersion\Run and HKLM\Software\Microsoft\Windows\CurrentVersion\Run, and by placing shortcuts or files in Startup folders.
"Sandworm Team used UPX to pack a copy of Mimikatz"; "APT38 has used several code packing methods such as Themida, Enigma, VMProtect, and Obsidium"; "Lazarus Group packed malicious .db files with Themida to evade detection."
actors used the following command to rename one of their tools to a benign file name: ren "%temp%\upload" audiodg.exe ... APT1 ... used ... AcroRD32.exe ... as a name for malware ... APT28 ... changed extensions on files containing exfiltrated data to make them appear benign ... APT32 has renamed a NetCat binary to kb-10233.exe to masquerade as a Windows update.
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 collecting the username, identifying the current user, enumerating logged-on users, or running commands such as whoami, query user, and quser to determine user context on compromised systems.
Several entries describe identifying whether the current user has admin privileges, determining privilege level, identifying groups the user belongs to, or verifying execution as SYSTEM.
The content repeatedly describes malware and threat actors collecting OS version, computer name, architecture, CPU, memory, disk, BIOS, language, and other host details; examples include use of commands such as ver, systeminfo, hostname, uname -m, and WMI to gather host information.
“actors used the following commands… to enumerate user accounts: net user >> %temp%\download; net user /domain >> %temp%\download … APT1 used the commands net localgroup, net user, and net group to find accounts… APT32 enumerated administrative users using the commands net localgroup administrators … OilRig has run net user, net user /domain, net group "domain admins" /domain …”
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.
APT41 used the Steam community page as a fallback mechanism for C2. Bazar has the ability to use an alternative C2 server if the primary server fails. BISCUIT malware contains a secondary fallback command and control server that is contacted after the primary command and control server.
ADVSTORESHELL exfiltrates data over the same channel used for C2... Agrius exfiltrated staged data using tools such as Putty and WinSCP, communicating with command and control servers... numerous malware and groups sent victim data, files, credentials, or host information over existing C2 channels.
33 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
Backdoor that tests the privilege level of the compromised user.
Malware that uses alternate ports for fallback C2 communication.
Malware that persists via a Start menu shortcut and/or a Registry Run key.
Malware that may save itself under the name of a legitimate Windows service binary.
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.