DecliningWindowsCredential theft
Malware Intelligence

SantaStealer

SantaStealer collects documents, credentials, wallets and data from many applications. It aims to run entirely in memory to evade file-based detection; data is compressed and sent in 10 MB chunks over unencrypted HTTP.

Activity map

Activity mapExecutionPackagingExfiltrationEXEPayloadFrom the temporary folder…SantaStealerInfostealerData collection13 targetsLog archiveC2 server
Executable payloadFileDark Radar evidence
Malicious payloadSantaStealer · Infostealer

SantaStealer collects documents, credentials, wallets and data from many applications. It aims to run entirely in memory to evade file-based detection; data is compressed and sent in 10 MB chunks over unencrypted HTTP.

Environment information

  • Operating system
  • Hardware
  • IP and location
  • Installed software
  • Screenshot
  • Desktop files

Credentials and application data

  • Saved passwords
  • Session cookies
  • Autofill
  • Saved cards
  • Telegram
  • Steam
  • Discord
  • Exodus
  • MetaMask
Dark Radar infection records
2,291
Latest infection record
1 April 2026
Malware type
Infostealer
First seen
2025
01

Overview

Ranks 44 of 52 families in Dark Radar data, with 2,291 infection records.

02

Origin and evolution

  1. 2025Announced on forums and analyzed.Rapid7
03

Technical profile

Malware typeInfostealer
Target operating systemWindows
Primary purposeData theft
Threat categoryCredential theft
Distribution modelSold on forums
First seen2025
Infected systemsWindows 10 56.1%, Windows 11 40.5%
Public source confidenceMedium
04

Targeted applications

13 applications6 categories
05

Data collection

Credentials

  • Browser passwords100%Verified
  • Session cookies97.1%Dark Radar observation
  • Refreshing expired sessions—
  • Autofill97.1%Dark Radar observation
  • macOS Keychain—
  • 2FA and password managers—

Financial

  • Saved cards15.6%Dark Radar observation
  • Desktop crypto wallets60.1%Verified
  • Wallet extensions—
  • Clipboard address replacement—

Applications

  • Email clients—
  • FTP clients—
  • VPN clients—
  • Messaging applications20.2%Reported
  • Gaming platforms16.2%Dark Radar observation

System

  • File collection82.7%Verified
  • Screenshot91.3%Dark Radar observation
  • System inventory97.1%Dark Radar observation
06

File system

User profile (%USERPROFILE%)
File details are in Dark Radar IntelligenceOpen in Intelligence
07

How it works

  1. 1Execution and evasion

    Dark Radar observation

    The payload ran from the temporary folder (latest 173 logs, 88.6%).

    The payload ran from the ProgramData folder (latest 173 logs, 6.6%).

    T1204.002User Execution: Malicious FileT1620Reflective Code Loading

    Breaking point: Unsigned files running from user folders and injections into .NET tools are stopped by application control and EDR.

  2. 2Discovery

    Dark Radar observation

    Infected systems: Windows 10 56.1%, Windows 11 40.5%.

    T1082System Information Discovery

    Breaking point: Bulk system and security software queries from a short-lived process trigger an EDR alert.

  3. 3Data collection

    Dark Radar observation

    Data found in the latest 173 logs: password file 100%, cookies 97.1%, autofill 97.1%, cards 15.6%, wallets 60.1%.

    T1555.003Credentials from Web BrowsersT1539Steal Web Session CookieT1005Data from Local SystemT1560Archive Collected Data

    Breaking point: A process other than the browser reading browser profile files is blocked or triggers an alert.

  4. 4Exfiltration and C2

    T1071.001Web ProtocolsT1041Exfiltration Over C2 Channel

    Breaking point: Traffic to newly registered domains, direct IP addresses and non-standard ports is blocked.

08

Network communication

This section is in Dark Radar IntelligenceOpen in Intelligence
09

MITRE ATT&CK

Execution
Credential Access
Discovery
Collection
Command and Control
Exfiltration
Defense Evasion
10

IOCs and detection

This section is in Dark Radar IntelligenceOpen in Intelligence
11

Risk and impact

  • Stolen session cookies are enough to take over cloud, email and SaaS sessions without a password or multi-factor authentication prompt.
  • Corporate passwords saved on personal devices also leak through infections outside the corporate network; these logs are sold to initial access brokers.
  • Log archives are reshared for years; as long as the password is not changed, the same credential can be used again and again.
  • Compromised email, messaging and social media accounts become the next link in phishing and malware distribution.
12

Defense

  • When an infection is detected, revoke not only the password but all related sessions and access tokens.
  • Turn off password saving in the browser through corporate policy; use a corporate password manager.
  • Move to phishing-resistant multi-factor authentication (FIDO2/passkey); bind sessions to the device.
  • Block setup files downloaded from unlicensed software, game cheats and sponsored search results.
  • Monitor flows where the user runs a command by pasting it into the Run dialog or terminal (ClickFix) with endpoint rules.
  • Continuously monitor your corporate domains and employee email addresses in stealer logs with Dark Radar.
13

Learning center

How does this malware spread?
  • The payload ran from the temporary folder (latest 173 logs, 88.6%).
  • The payload ran from the ProgramData folder (latest 173 logs, 6.6%).
  • Infostealer families mostly spread through unlicensed software, fake updates, sponsored search ads and phishing emails.
How can its presence on a system be detected?
  • Sign-ins to accounts from an unrecognized country or device.
  • A new infostealer log in Dark Radar for your corporate domain or an employee email address.
Which Windows artifacts should be examined?
  • Prefetch (C:\Windows\Prefetch) — shows that a short-lived payload ran.
  • Amcache.hve and ShimCache — path and hash of the executed file.
  • Downloads folder and Zone.Identifier stream — the address the file was downloaded from.
  • Browser history — the fake download page or fake CAPTCHA address.
  • RunMRU registry key — commands pasted into the Run dialog.
  • Randomly named folders and DLLs under %TEMP% and %LOCALAPPDATA%.
Which log records matter?
  • Sysmon Event 1 / Security 4688Process creation: unsigned processes starting from Temp and Downloads folders, mshta, powershell -enc chains.
  • Sysmon Olay 11 / 23File creation and deletion: self-deleting payloads, DLLs dropped under Temp.
  • Sysmon Olay 3 / 22Network connection and DNS query: to newly registered domains, C2 resolution via Telegram, Steam or Pastebin.
  • Object access auditing (4663)A process other than the browser reading Login Data, Cookies and Local State files.
  • PowerShell 4104Script block logging: obfuscated downloader commands.
  • Identity provider sign-in logsSessions after the infection from a different country and device, without a multi-factor authentication prompt.
Which MITRE techniques is it associated with?
T1204.002User Execution: Malicious FileT1555.003Credentials from Web BrowsersT1539Steal Web Session CookieT1082System Information DiscoveryT1005Data from Local SystemT1071.001Web ProtocolsT1041Exfiltration Over C2 ChannelT1560Archive Collected DataT1620Reflective Code Loading
How should a SOC analyst respond?
  1. Isolate the device from the network; do not reinstall it before taking memory and disk images.
  2. Determine the infection date; list all accounts that were signed in on the device after that date.
  3. Change the passwords of these accounts, revoke their sessions and access tokens, and re-enroll multi-factor authentication devices.
  4. Search identity provider and SaaS logs for new country, device and token usage after the infection.
  5. If a recovery phrase or wallet file was exposed, move the assets to a new wallet.
  6. Find the initial access path (email, ad, unlicensed software, fake CAPTCHA) and check other users who used the same path.
  7. Reinstall the device from a clean image.
14

Sources

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