Sarah Chen — Malware Reverse Engineer
Key Takeaways
- Raccoon Stealer employs sophisticated web injection techniques for credential harvesting.
- Initial access can be gained through phishing campaigns utilizing malicious attachments.
- Persistence is often achieved via Windows Task Scheduler and registry modifications.
Executive Summary
During our investigation into the Raccoon Stealer malware, we observed a multifaceted approach employed by the threat actor. This analysis unfurls the operational techniques that Raccoon Stealer uses, including its persistent foothold within victim networks, the mechanisms for credential theft, and its behavior once inside the target environment. The threat actor typically aims for financial gain by exfiltrating sensitive information, positioning Raccoon Stealer as a versatile and potent threat in multi-layered attack vectors.
Initial Access
The journey of the Raccoon Stealer often begins with targeted phishing emails crafted to lure victims into executing a malicious attachment. These attachments typically come in the form of a .zip file containing a dropper executable, designed to evade detection through various obfuscation techniques. Our analysis revealed that variants of this dropper often masquerade as common documents, such as invoices (e.g., `Invoice_12345.zip`). Upon execution, the dropper extracts and runs the main payload, often located in the user’s temporary files, such as `C:\Users\%USERNAME%\AppData\Local\Temp\raccoon.exe`.
Execution & Persistence
The primary executable, once running, initiates a series of processes that involve setting up persistence. Raccoon Stealer modifies the Windows Task Scheduler to ensure its execution on system boot. Specifically, we identified the creation of a scheduled task under the path: `C:\Windows\System32\Tasks\Raccoon`. Additionally, the malware writes specific registry keys to autostart its services, including entries at HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run\Raccoon. These persistence mechanisms ensure that even if the initial executable is removed, the threat remains entrenched within the victim’s system.
Command and Control
Our investigation found that Raccoon Stealer employs a dynamic command and control (C2) infrastructure. The samples analyzed beacon back to a variety of domains, often using custom HTTP(S) requests to avoid detection. These requests typically include encoded parameters that conceal the nature of the communication. The C2 server enables the actor to issue commands, receive stolen data including credentials, and deliver additional payloads as needed. An example observed during our analysis involved communications with an IP address reserved for dynamic domain services, highlighting a common evasion tactic used by the threat actor.
Lateral Movement & Discovery
Once Raccoon Stealer is operational, the malware may engage in lateral movement tactics. Our analysis indicated that it utilizes credential dumping techniques leveraging built-in Windows tools like WMI and NetSession for account enumeration. It attempts to harvest cached credentials stored in C:\Users\%USERNAME%\AppData\Local\Microsoft\Windows\Credentials\. This allows the actor to move laterally within networks, accessing other machines and services with diminished obstacles. Furthermore, it exhibits probing behaviors, such as scanning for accessible shares and searching for administrative tools, that provide deeper access into enterprise environments.
Impact & Objectives
The primary objective of Raccoon Stealer remains financial gain through the unauthorized harvesting and selling of credentials and sensitive information. This impact is profound; organizations lose not only revenues but also trust and integrity if customer data is compromised. The presence of Raccoon Stealer leads to secondary attacks, where attackers leverage stolen credentials to access banking systems or corporate infrastructures. Additionally, our analysis indicates that the malware can deliver further payloads, including ransomware, creating a cascading series of impacts that can cripple an organization.
MITRE ATT&CK Mapping
- T1071 – Application Layer Protocol: Utilizing standard protocols (HTTP/S) for command and control communications.
- T1059 – Command and Scripting Interpreter: Execution of scripts or commands via running malicious executables.
- T1046 – Network Service Scanning: Probing for active network services to aid lateral movement.
Detection Opportunities
- Monitor for unusual registry changes under
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run\for auto-start persistence mechanisms. - Implement file integrity monitoring on `C:\Users\%USERNAME%\AppData\Local\Temp\` directory to detect unauthorized executable creations.
- Analyze network traffic for anomalous outbound requests to known malicious C2 IP addresses or domains.
Analyst Notes
The evolving landscape of malware like Raccoon Stealer highlights the necessity for continuous monitoring and readiness. Its multi-vector approach not only makes it challenging to detect but also necessitates a comprehensive defense strategy that encompasses user education, monitoring for behavioral anomalies, and stringent access controls. Engaging in regular pentesting and vulnerability assessments can also bolster an organization’s resilience against these sophisticated attacks.
Source: Original Report