Full Report
WarmCookie is a malware family that emerged in April 2024 and has been distributed via regularly conducted malspam and malvertising campaigns.
Analysis Summary
# Tool/Technique: WarmCookie (BadSpace)
## Overview
WarmCookie, also known as BadSpace, is a malware family observed since at least April 2024. It is primarily used for initial access and establishing persistence within compromised environments, facilitating the delivery of secondary payloads such as CSharp-Streamer-RAT and Cobalt Strike. It is associated with post-compromise activity that overlaps with TA866.
## Technical Details
- Type: Malware family
- Platform: Windows (Implied by use of PowerShell, Bitsadmin, and observed DLL payload)
- Capabilities: Payload deployment, file manipulation, command execution, screenshot collection, and persistence mechanisms.
- First Seen: April 2024
## MITRE ATT&CK Mapping
* M1047 - Initial Access
* M1027 - Persistence
* M1059 - Command and Control (Implied by C2 delivery)
*(Note: Specific technique mappings require deeper analysis of the malware's full capabilities, but the overview strongly suggests these tactics.)*
## Functionality
### Core Capabilities
- Initial infection via malspam or malvertising campaigns.
- Uses malicious JavaScript downloaders (often delivered via linked PDFs or ZIP archives).
- Deobfuscates and executes a PowerShell command leveraging `Bitsadmin` to retrieve and execute the WarmCookie DLL payload.
- Provides mechanisms for long-term access and persistence.
### Advanced Features
- Continuous improvement of tooling (new versions observed in September 2024 included significant additions/changes).
- Capability to collect screenshots from the compromised host.
- Used to stage and deliver secondary malware, including CSharp-Streamer-RAT and Cobalt Strike. The overlap with Resident backdoor suggests advanced post-compromise implant capabilities.
## Indicators of Compromise
- File Hashes: [Not provided in the summary text, directed to GitHub repository]
- File Names: Randomized filenames in attachments (e.g., `Attachment_[0-9]{3}\-[0-9]{3}\.pdf`).
- Registry Keys: [Not specified]
- Network Indicators: Malicious JavaScript files hosted on compromised web servers, sometimes leveraging the LandUpdates808 infrastructure cluster at paths like `/wp-content/upgrade/update[.]php`.
- Behavioral Indicators: Use of PowerShell execution chain involving `Bitsadmin` to fetch a DLL.
## Associated Threat Actors
- TA866 (Attribution based on overlapping activity patterns and infrastructure association).
## Detection Methods
- Signature-based detection: ClamAV signatures include `Win.Malware.Warmcookie-10036688-0`.
- Behavioral detection: Monitoring for PowerShell commands utilizing `Bitsadmin` to download and execute DLLs.
- YARA rules: [Not explicitly listed, but detection methods imply their usability].
- Snort Rules: SIDs 64139-64162 (Version 2) and 64153-64162, 301044-301050 (Version 3) are available.
## Mitigation Strategies
- Email filtering and security awareness training to mitigate malspam/phishing related to invoice/job agency lures.
- Web security solutions (e.g., Cisco Secure Web Appliance) to block access to malicious distribution sites.
- Use of Cisco Duo for multi-factor authentication, limiting impact if initial access is successful.
- Implement strong endpoint detection and response to monitor for suspicious PowerShell execution chains involving BITS administration.
## Related Tools/Techniques
- CSharp-Streamer-RAT (Secondary payload)
- Cobalt Strike (Secondary payload)
- Resident (Attributed backdoor developed by the same actor)
- LandUpdates808 (Associated distribution infrastructure cluster)