StopRansomware: Unpacking the Ghost (Cring) Ransomware Threat
Published: February 19, 2025Source: CISA, FBI, and MS-ISAC
In a bid to empower network defenders worldwide, the FBI, Cybersecurity and Infrastructure Security Agency (CISA), and the Multi-State Information Sharing and Analysis Center (MS-ISAC) have released a comprehensive advisory on the Ghost (Cring) ransomware. This advisory—an integral component of the ongoing #StopRansomware campaign—details how the Ghost actors are leveraging known vulnerabilities, rotating payloads, and using a myriad of tools to orchestrate attacks on organizations across the globe.
The advisory serves as a wake-up call for Windows users and administrators alike. Let’s dive into the key aspects of the report, examine the technical nuances, and outline actionable steps to mitigate the threat.
Overview: Who Are the Ghost Actors?
Key Points:- Origin & Motivation:
The attackers, often attributed to groups based in China, are financially driven. They target organizations regardless of size—from critical infrastructure and government networks to educational institutions and SMBs. - Target Vulnerabilities:
Since early 2021, these adversaries have exploited outdated and unpatched internet-facing systems. Their toolkit includes ransomware variants under names like Ghost, Cring, Crypt3r, and Phantom—all of which use changing payloads (e.g., Cring.exe, Ghost.exe, ElysiumO.exe, and Locker.exe). - Operational Tactics:
By frequently rotating ransomware executable names, altering file extensions, and using various ransom note templates along with multiple email addresses, the group complicates attribution and detection.
Attack Phases: A Step-by-Step Breakdown
The advisory maps Ghost actors’ operations to the MITRE ATT&CK® framework (version 16.1), providing guidance on how each phase of the attack is executed. Here’s a succinct overview:1. Initial Access
- Exploitation of Vulnerable Services:
Ghost actors target public-facing applications that often run outdated software and firmware. They exploit vulnerabilities such as: - Fortinet FortiOS: CVE-2018-13379
- Adobe ColdFusion: CVE-2010-2861 and CVE-2009-3960
- Microsoft SharePoint/Exchange: CVE-2019-0604, CVE-2021-34473, CVE-2021-34523, and CVE-2021-31207 (the infamous ProxyShell chain)
- The Result:
With a successful exploit, adversaries gain initial footholds in networks. This underscores the importance of applying timely patches and security updates.
2. Execution
- Malicious Payload Deployment:
After establishing access, attackers upload a web shell to the compromised server. They then leverage the Windows Command Prompt or PowerShell to download and execute Cobalt Strike Beacon malware.
3. Persistence
- Short-Lived Residence:
While long-term persistence isn’t a top objective (as Ghost actors typically move to the next target within a few days), they sometimes: - Create local or domain accounts to extend their access.
- Change passwords to lock out legitimate users.
- Web Shells Revisited:
Additional web shells may also be deployed to re-establish connectivity if initial vectors are closed.
4. Privilege Escalation and Credential Access
- Elevating Access:
The group leverages functions within Cobalt Strike to steal process tokens from SYSTEM accounts. They also use various open-source tools like: - SharpZeroLogon
- BadPotato and its counterpart GodPotato
- Credential Harvesting:
With tools such as the built-in Cobalt Strike “hashdump” or Mimikatz, they retrieve passwords and hashes from the compromised systems, thus paving the way for further lateral movement.
5. Defense Evasion, Discovery, and Lateral Movement
- Evading Detection:
Ghost actors routinely disable antivirus programs (for example, by issuing commands to disable Windows Defender) and hide malicious processes using PowerShell techniques that conceal command windows. - Reconnaissance:
Investigation tools like SharpShares, Ladon 911, and SharpNBTScan help them map the network by discovering open shares, active hosts, and system processes. - Lateral Spread:
Using elevated privileges and tools such as WMIC, the attackers propagate the attack to other systems by executing encoded PowerShell commands.
6. Data Exfiltration and Command & Control
- Data Theft Claims:
Although ransom notes suggest that exfiltrated data will be sold if the ransom isn’t paid, actual data exfiltration is typically limited. The advisory notes transfers are often under a few hundred gigabytes, making the financial extortion primarily about the encrypted files. - Direct C2 Connections:
Instead of using easily traceable domain names, the attackers often reference an IP address directly to download malicious payloads. Communication is routed over HTTP/HTTPS, and even their email communications with victims use legitimate, encrypted services (e.g., Tutanota, ProtonMail).
7. Impact and Encryption
- System Lockdown:
Once deployed, the ransomware encrypts targeted directories or entire systems. To complicate recovery efforts, it deletes Volume Shadow Copies and clears event logs—making forensic analysis challenging. - The Ransom Demand:
Victims are typically asked to pay tens to hundreds of thousands of dollars in cryptocurrency for decryption keys.
Mitigation Measures: Fortify Your Windows Environment
The advisory isn’t just about what the attackers are doing—it’s also a practical guide on how organizations can mitigate the impact:- Regular Backups:
Ensure that backups are not only current but also stored offline or on segregated networks. This offers a critical fallback to restore operations without paying a ransom. - Timely Patching:
Apply security updates to operating systems, applications, and firmware promptly. Many of these attacks succeed due to unpatched vulnerabilities. - Network Segmentation:
Divide your network into isolated segments to interrupt the spread of an attack. Effective segmentation can keep an initial compromise from turning into a full-blown system meltdown. - Enforce Phishing-Resistant MFA:
Require multi-factor authentication for all privileged accounts and critical services. This additional layer makes it exponentially harder for attackers to use stolen credentials. - User Training and Awareness:
Educate users to recognize phishing attempts—a key vector for many ransomware attacks. - Implement Application and Script Allowlisting:
Restrict execution to only approved applications and scripts. This limits the chances of unauthorized programs running on your systems. - Monitor for Abnormal Behavior:
Stay alert for unusual PowerShell activity or unknown processes running in your environment. Early detection is vital in stopping an attack before it escalates. - Disable Unused Services:
Reduce your exposure by turning off unused ports (such as RDP, FTP, and SMB) or restricting them behind properly secure VPNs or firewalls.
Technical Analysis and Wider Implications
Leveraging the MITRE ATT&CK Framework
The advisory maps each phase of the attack to the MITRE ATT&CK framework (version 16.1), which helps IT professionals understand adversary behavior in a structured way. For instance:- T1190 – Exploit Public-Facing Application: Highlights how attackers use known vulnerabilities.
- T1059 – Command and Scripting Interpreter: Explains the abuse of PowerShell and CMD for downloading payloads.
- T1486 – Data Encrypted for Impact: Captures the essence of ransomware activity—encrypting data to force a ransom payment.
The Double-Edged Sword of Legitimate Tools
A notable point in the advisory is the use of commercially available tools like Cobalt Strike. Originally designed for penetration testing and security simulations, when these tools fall into the wrong hands, they enable adversaries to mimic legitimate traffic—and thereby bypass traditional security checks. This reinforces a growing industry sentiment: proper configuration and monitoring of tools that can be used for both good and ill are more critical than ever.A Historical Perspective on Ransomware Evolution
Ransomware has come a long way from its early, relatively unsophisticated incarnations. Today’s ransomware groups, including Ghost (Cring), have evolved into organized cybercriminal enterprises. Their operations are characterized by:- Automation and Rapid Execution:
Many attacks progress from initial compromise to encryption within the span of a single day. - Adaptability:
Constantly rotating their TTPs—changing file extensions, ransom note templates, and command syntax—helps them fly under the radar.
Actionable Guidance for Windows Administrators
If you’re responsible for managing Windows systems, consider these steps as part of your routine security checklist:- Assess Your Exposure:
- Audit public-facing applications.
- Identify vulnerable software or firmware that may not have been patched.
- Enhance Detection Capabilities:
- Leverage tools to monitor unusual PowerShell activity.
- Set up alerts for non-standard network scans, unexpected account creations, or unusual file modifications.
- Reinforce Defensive Measures:
- Apply the principle of least privilege across your network.
- Strengthen email security with DMARC, SPF, and DKIM to prevent spoofing.
- Test Your Incident Response:
- Run simulated scenarios to ensure that your backups, network segmentation, and monitoring systems perform as expected during an attack.
- Stay Informed:
- Regularly check updates from official agencies like CISA and engage in community forums for the latest cybersecurity insights.
Conclusion
The #StopRansomware advisory on Ghost (Cring) ransomware is a clarion call for all organizations to tighten their cybersecurity posture. With attackers exploiting unpatched vulnerabilities, abusing legitimate system tools, and adopting ever-changing methodologies, it has never been more crucial for Windows administrators to remain vigilant.By:
- Maintaining robust backup strategies,
- Swiftly applying security patches,
- Segmenting networks to halt lateral movement, and
- Educating end users about phishing threats,
In the high-stakes realm of cybersecurity, falling behind is not an option. As ransomware tactics evolve, so too must your defensive strategies. Stay proactive, stay informed, and most importantly—stay secure.
For ongoing discussions and additional insights into Windows security—including measures to counter ransomware—visit the Windows Forum.
Note: This analysis is based on the joint advisory released by CISA, FBI, and MS-ISAC. While the attackers’ techniques evolve rapidly, the core principles of defense—patching, monitoring, and network segmentation—remain critical pillars in the fight against ransomware.
Source: CISA #StopRansomware: Ghost (Cring) Ransomware | CISA
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