Skip to content

Response, New York. Noah Park: Check Point Patches Actively Exploited Management Server Path Traversal. Detection, Dallas. Ava Okello: Report Finds Nearly Half of Deployed Detections Need Attention Before SOCs Can Trust Them.

SOCtember

Always First. Fast SOC News.

Group-IB header illustration for its SiriusQT analysis, a translucent hardware device lit in red.
Image: Group-IB, header illustration for "Inside SiriusQT: A Seriously Skilled RAT," Oct. 22, 2026 (fair use).

Detection

Group-IB Says SiriusQT, a $500 Windows RAT Whose Leaked Licenses Outnumber Paid Ones Three to One, Can Seed the Default User Profile So It Starts in Accounts That Do Not Exist Yet

Group-IB's teardown of the RAT, sold since April and widely shared in cracked builds, shows six persistence options, an HVNC hidden desktop, a recovery panel with more than 100 credential targets and a Windows Update disguise. It also publishes YARA rules and indicators. Where defenders should look first.

Ava Okello, DetectionLondon5 min read

LONDON - A Windows remote access trojan that its reseller prices at $500 for a lifetime license is spreading mostly in copies nobody paid for, and its persistence options include a trick that plants it in user accounts that have not been created yet, according to an analysis Group-IB published on Thursday.

SiriusQT has been for sale on dark web forums since April 2026, Group-IB senior reverse engineer Riccardo Di Pietro wrote. The tool's about screen names its author as "Amonus," but the only visible seller is GhostKernel, a group active on underground forums and Telegram that also advertised the BTMob Android RAT. At least 30 buyers held a valid license. Of 146 unique licenses Group-IB extracted from samples, 110 were leaked, almost 75 percent of the pool, and promotional screenshots of the server carried the window title "Sirius Cracked by Claude." Distributors of cracked builds turned up on dark web forums and even GitHub repositories, creating a second, free market alongside the paid one.

Group-IB found more than 280 SiriusQT clients in public samples. By VirusTotal submissions, Britain, France, Germany and the Netherlands account for more than half of the observed locations, although that data mixes real victims with operator tests and sandbox runs.

Six ways to start, and one that waits

The builder lets an operator pick from six startup methods: a Run key under HKCU, a scheduled task, a Startup folder shortcut, the UserInitMprLogonScript value pointing to a logon.cmd script, the BootExecute value under Session Manager when it has administrator rights, and the Default User profile. Unless the operator sets custom names, the Run value, the scheduled task and the shortcut description all use Windows Update.

The last option is the one to note. Windows builds every new profile from C:\Users\Default, and SiriusQT loads that profile's NTUSER.DAT with RegLoadKeyA, writes an autorun value, and unloads it with RegUnLoadKeyA. The result, Group-IB says, is persistence seeded both in the current user and in future accounts created on the same machine.

SiriusQT's server-side credential recovery panel, with checkboxes for cryptocurrency wallets, messengers, browsers, VPN clients, games, password managers and other sources.
Screenshot: Group-IB, Figure 24, the credential recovery interface in the SiriusQT server-side component, Oct. 22, 2026 (fair use).

What the implant does

By default the client installs as %APPDATA%\Microsoft\svchost.exe, with %TEMP%\msupdate as a fallback, according to the configuration fields Group-IB decoded. It resolves Windows APIs at run time with a custom FNV-1 hash, offers process hollowing, early-bird APC and remote thread injection, and logs keystrokes with a low-level keyboard hook while watching the clipboard. Its recovery panel covers more than 100 sources, among them wallets, messengers, browsers, VPN clients, password managers, developer tools, RDP and mail clients, and it checks whether stolen Discord tokens still work.

For hands-on fraud, SiriusQT runs an HVNC hidden desktop. It launches a Chromium-based browser with a custom user data directory and a "Welcome to HVNC !" start page, and lets the operator clone a browser profile, which Group-IB says amounts to complete session theft. The builder can also block execution in CIS countries and check for virtual machines.

Group-IB's SiriusQT Global Distribution Map, a pie chart of client locations from VirusTotal submissions led by Britain, France, the Netherlands and Germany.
Image: Group-IB, Figure 8, distribution of SiriusQT clients by public VirusTotal submissions, Oct. 22, 2026 (fair use).

Traffic runs over TCP with a cleartext four-byte length prefix and a custom encrypted payload. Many of the endpoints Group-IB lists use port 4449, and the 32-byte license token embedded in each client lets analysts cluster samples and track how a builder was used across campaigns. Group-IB says the client is barely obfuscated, which explains its high detection rate, and that SiriusQT appears to arrive as a last-stage payload after the UpCrypter loader. One Google Cloud address in the data, 34[.]41[.]139[.]193, has also been seen in past NetWire campaigns.

Group-IB chart of SiriusQT genuine licenses in use by duration, with 30-day and lifetime licenses most common and unusual 14, 28, 45 and 99-day terms.
Image: Group-IB, Figure 7, distribution of SiriusQT genuine license types in use, Oct. 22, 2026 (fair use).

What to hunt for

  • Writes to C:\Users\Default\NTUSER.DAT, or registry hive loads and unloads of the Default User hive, by anything other than imaging or provisioning tools.
  • A new or changed BootExecute value under HKLM\SYSTEM\CurrentControlSet\Control\Session Manager, and a UserInitMprLogonScript value under HKCU\Environment.
  • Run keys, scheduled tasks or Startup shortcuts named Windows Update or WindowsUpdate.lnk.
  • svchost.exe running from %APPDATA%\Microsoft or %TEMP%\msupdate.
  • Chromium-based browsers started with an unusual user data directory and a data:text/html start page.
  • Outbound TCP to port 4449 and the published indicators, including 23[.]132[.]164[.]14:4449 and server[.]activeworkshops[.]com.

Group-IB published four YARA rules covering the server, the native client, the .NET loader and the HVNC helper DLL, along with file hashes, network indicators and a script to decrypt the server's appdata.dat file.

Sources:


Ava Okello covers detection engineering, EDR telemetry and SOC hunting for SOCtember from London.

Related stories

Detection desk