# Snake Keylogger Info-Stealer Profile
Snake Keylogger, also catalogued under the alias 404 Keylogger, is a commercially distributed credential-theft tool built on the .NET framework and sold through subscription tiers on underground cybercriminal markets. It entered widespread operational use in November 2020 and has maintained consistent placement in top-ten malware rankings since that time. The tool exists because credential theft is the highest-return, lowest-barrier entry point into corporate environments: stolen usernames and passwords bypass perimeter controls entirely, rendering expensive firewall and intrusion-detection investments irrelevant. Snake Keylogger solves a specific problem for low-to-mid-tier threat actors who lack the development skills to build bespoke malware, giving them a reliable, maintained, and regularly updated credential harvester for a monthly subscription fee.
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Snake Keylogger is a .NET-based infostealer and keylogger distributed under a malware-as-a-service (MaaS) model. Its core function is the systematic collection of authentication credentials from a compromised host, followed by covert exfiltration of that data to attacker-controlled infrastructure. The tool combines traditional keystroke logging with modern browser credential extraction, WiFi password harvesting, and clipboard monitoring into a single package that requires minimal technical expertise to deploy.
The malware exists because credential theft has become the most reliable path to enterprise compromise. While organizations invest millions in perimeter defenses, endpoint protection, and security awareness training, a single set of stolen credentials can bypass all these controls. A user's saved password to the company VPN, harvested by Snake Keylogger and sold on a criminal marketplace for $5, provides the same network access that would cost a sophisticated attacker weeks of reconnaissance and exploitation development.
Snake Keylogger fills a specific niche in the cybercriminal ecosystem. High-tier threat actors build custom malware tailored to their targets. Low-tier actors rely on freely available tools that are quickly detected. Snake Keylogger targets the middle tier: actors with budgets to pay monthly subscription fees (typically $25-100) but insufficient development skills to create their own tools. This positioning has made it one of the most consistently deployed infostealers since 2020, with new variants appearing monthly as the developers add features and update evasion techniques.
The malware is categorized within the infostealer family but distinguished from pure browser credential theft tools by its keylogging capability. While tools like RedLine Stealer focus primarily on extracting saved passwords from browser databases, Snake Keylogger also captures credentials typed manually, including those for applications that do not save passwords or newly created accounts where passwords have not yet been saved. This dual capability makes it particularly effective against organizations with security policies prohibiting browser password storage.
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Snake Keylogger operations follow a predictable sequence from initial delivery through credential exfiltration. Understanding this sequence is essential for building effective detection and response capabilities.
Initial Delivery and Execution
The primary delivery vector is phishing email with malicious attachments. Attackers craft messages impersonating business correspondence: invoice notifications, shipping confirmations, purchase orders, or legal documents. The attachment types have evolved to bypass common email security configurations. Early campaigns used Office documents with VBA macros. Current campaigns prefer ISO disk images, HTML files with embedded JavaScript (HTML smuggling), and password-protected archive files.
ISO files are particularly effective because they bypass Mark-of-the-Web protections when mounted. The ISO contains a Windows executable that appears to be a legitimate document viewer or installer. When the victim double-clicks the executable, it functions as a loader that decodes the Snake Keylogger payload from embedded data or downloads it from a remote server.
HTML smuggling reconstructs the malicious payload client-side using JavaScript, allowing the attack to pass through email gateways that scan for malicious attachments. The HTML file contains base64-encoded fragments of the Snake Keylogger binary. When opened in a browser, JavaScript reassembles these fragments into a complete executable and automatically downloads it to the victim's Downloads folder.
Process Injection and Persistence
Once the initial loader executes, it deploys Snake Keylogger using process hollowing or DLL injection techniques. Process hollowing is the most commonly observed method: the loader spawns a legitimate Windows process such as MSBuild.exe, RegAsm.exe, or InstallUtil.exe in a suspended state, unmaps the legitimate code from memory, injects the Snake Keylogger payload, and resumes execution. This makes the malicious activity appear to originate from a trusted Microsoft binary.
Persistence mechanisms include scheduled tasks, registry Run keys, and startup folder entries. Scheduled task names are chosen to blend with legitimate system maintenance: "Windows_Security_Health_Service", "Microsoft_Edge_Update_Task", or names derived from software installed on the host. The tasks are configured to execute at user logon or at regular intervals, ensuring the keylogger restarts after system reboots.
Credential Collection Operations
The core collection phase targets multiple data sources simultaneously through parallel threads. Browser credential extraction accesses SQLite databases where Chromium-based browsers store saved passwords. These databases are encrypted using Windows Data Protection API (DPAPI), but Snake Keylogger calls CryptUnprotectData to decrypt them using the logged-in user's context. This requires no privilege escalation because users can decrypt their own DPAPI-protected data. Supported browsers include Chrome, Edge, Firefox, Opera, Brave, and over 30 additional variants.
Email client targeting extracts account configurations from Microsoft Outlook, Mozilla Thunderbird, and Foxmail. The malware reads application configuration files and registry entries to capture SMTP, IMAP, and POP3 credentials along with server settings. This information allows attackers to access email accounts directly rather than relying on web interfaces.
The keylogger component uses SetWindowsHookEx with the WH_KEYBOARD_LL flag to capture all keyboard input system-wide. Keystrokes are filtered and organized by window title to provide context about where credentials were entered. The captured data is stored in encrypted log files that are periodically transmitted to command and control infrastructure.
Clipboard monitoring operates as a background thread that polls clipboard contents at regular intervals. When cryptocurrency wallet addresses are detected (identified by format patterns for Bitcoin, Ethereum, and other major cryptocurrencies), the malware logs the address and may replace it with an attacker-controlled address. This clipboard hijacking can redirect cryptocurrency transactions without user awareness.
Advanced Collection Features
Recent Snake Keylogger variants include screenshot capture functionality that saves desktop images at configurable intervals. Screenshots capture information that keylogging cannot, such as virtual keyboards, password managers that prevent keystroke capture, and visual content like QR codes or document contents.
WiFi credential extraction queries the Windows wireless profile store using netsh commands or direct API calls to WlanGetProfile. This captures passwords for wireless networks the victim has connected to previously, providing attackers with information about locations the victim frequents and potential access to those networks.
Evasion and Anti-Analysis
Snake Keylogger applies multiple layers of obfuscation to its .NET assemblies. Control flow obfuscation scrambles the execution path to make reverse engineering difficult. String encryption hides readable text that could be used for signatures. Name mangling replaces meaningful function and variable names with random strings.
Runtime evasion includes anti-debugging checks that detect analysis environments and alter behavior. AMSI (Antimalware Scan Interface) patching modifies the AmsiScanBuffer function in memory to prevent script-based detection. Some variants check for virtual machine artifacts and refuse to execute in analysis environments.
Data Exfiltration
Collected credentials and data are staged locally in encrypted files before transmission. Exfiltration channels vary by build but commonly include SMTP (email to attacker-controlled addresses), FTP uploads, Telegram Bot API, and Discord webhooks. The Telegram and Discord channels are particularly problematic for detection because they use HTTPS connections to legitimate services, making the traffic appear benign without deep packet inspection.
Real-World Attack Scenario
A healthcare organization's billing department receives an email appearing to come from an insurance company, containing an ISO file labeled "Claim_Documentation_Q4.iso". The billing specialist mounts the ISO and runs the executable inside, expecting to see claim forms. Nothing visible happens, but Snake Keylogger executes inside MSBuild.exe, creates a scheduled task named "HealthService_Update", and begins collection. Over the following weeks, it harvests saved passwords from Chrome (including the organization's patient portal, billing system, and email), captures manually-typed credentials for financial systems, takes screenshots of patient records, and extracts WiFi passwords. All data is transmitted to a Telegram bot. Six weeks later, patient records appear on a dark web marketplace, and the organization discovers unauthorized access to their banking systems.
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Snake Keylogger infections create cascading consequences that extend far beyond the initially compromised endpoint. The harvested credentials enter the cybercriminal ecosystem through multiple channels: direct use by the initial attackers, sale on credential marketplaces, or distribution to specialized threat groups focused on specific attack types. A single infection can provide the initial access that enables business email compromise, ransomware deployment, or data theft operations.
The economic impact follows a predictable pattern. The direct cost to deploy Snake Keylogger is minimal: monthly subscription fees range from $25 to $100, making it accessible to low-sophistication actors. However, the downstream consequences for victim organizations can reach millions of dollars. Harvested VPN credentials sold to initial access brokers enable ransomware affiliates to enter corporate networks. Email credentials facilitate business email compromise schemes that redirect wire transfers. Banking credentials enable direct financial theft.
One documented consequence pattern involves credential propagation across business relationships. Because Snake Keylogger captures email content and contact lists in addition to credentials, attackers gain insight into the victim organization's partners, suppliers, and customers. This information enables highly credible spear-phishing campaigns targeting the victim's business network. Multiple threat intelligence firms have documented cases where Snake Keylogger infections at one organization led to successful attacks against their partners using insider information about business relationships and communication patterns.
The supply chain implications are particularly significant in industries with tight integration between organizations. A 2023 case study documented how Snake Keylogger infection at a logistics company provided credentials to a freight management platform. Attackers used these credentials to redirect shipments, alter delivery documentation, and coordinate cargo theft. The initial keylogger subscription cost under $50; the downstream theft exceeded $200,000 in diverted goods.
A critical misconception is that multi-factor authentication (MFA) provides complete protection against credential theft. While MFA significantly raises the barrier for account takeover, it does not eliminate the risk. Session cookie theft, increasingly added to infostealer capabilities, can bypass MFA by reusing authenticated session tokens. Additionally, many organizations implement MFA inconsistently, protecting some applications while leaving others vulnerable to credential-based access.
Another dangerous misconception is treating infostealer infections as "low severity" incidents because they do not deploy destructive payloads. This assessment is operationally incorrect. The absence of immediate visible damage makes infostealers more dangerous, not less, because they operate undetected for extended periods. Organizations typically discover infections only after credential misuse has already occurred, by which time the damage has compounded across multiple systems and potentially multiple organizations.
The regulatory and compliance implications are also significant. Depending on the industry and jurisdiction, credential theft may trigger data breach notification requirements even without evidence of data access. The harvested credentials themselves constitute personal information under many privacy regulations, and the additional data collected (screenshots, clipboard contents) may include protected information that requires disclosure.
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CDA approaches Snake Keylogger through the Planetary Defense Model with primary domain assignment to Threat Intelligence and Detection (TID), supported by Data Protection and Sovereignty (DPS). The operational methodology is Predictive Defense Intelligence (PDI): see the threat before it sees you. This means detecting Snake Keylogger campaigns before they reach organizational endpoints and preparing defenses based on campaign intelligence rather than waiting for post-infection indicators.
PDI applied to Snake Keylogger begins with continuous monitoring of underground forums, credential marketplaces, and phishing kit databases for organizational assets. When a domain's email addresses appear in targeting lists or stolen credential dumps, this provides early warning that an active campaign may be underway. CDA operationalizes this through structured intelligence feeds that correlate credential exposure data against organizational asset inventories daily, not quarterly.
The hunt-forward approach distinguishes CDA methodology from reactive security operations. Rather than waiting for endpoint detection alerts, CDA analysts run proactive threat hunts using current campaign indicators: searching for scheduled tasks with suspicious naming patterns consistent with Snake Keylogger persistence mechanisms, hunting for legitimate Microsoft binaries with unexpected network connections, and querying DNS logs for resolution of known Telegram Bot API endpoints from workstation subnets. This approach consistently reduces dwell time compared to reactive detection models.
From a DPS perspective, CDA treats credential exfiltration as a data sovereignty violation equivalent to intellectual property theft. This classification drives specific technical implementations: DLP policies configured to detect credential-formatted strings in outbound traffic, network egress monitoring for connections to Telegram and Discord APIs from non-user systems, and anomalous SMTP connection detection from workstation subnets.
CDA also extends the threat model to include supplier and partner risk. Because Snake Keylogger infections at third parties can enable targeted attacks against an organization using harvested business intelligence, CDA includes third-party credential exposure monitoring within the TID program scope. This approach recognizes that modern organizational boundaries extend beyond traditional network perimeters to include the extended ecosystem of business relationships.
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