This blog marks the beginning of a series based on the findings in the GRIT 2025 Ransomware and Cyber Threat Report. Each post in this series will dive into critical aspects of ransomware and cyber threats, providing actionable insights to help organizations strengthen their security posture. Today, we start by exploring post-compromise detection—a crucial element in mitigating the impact of ransomware attacks. By understanding and addressing key indicators of malicious activity, security teams can stay one step ahead of attackers.
The Importance of Post-Compromise Detection
While preventative measures like firewalls and endpoint protection are critical, no system is foolproof. Post-compromise detection serves as the last line of defense, allowing organizations to detect and respond to threats before they escalate. Early detection minimizes downtime, reduces financial and reputational damage, and helps safeguard critical data.
Key Indicators of Post-Compromise Activity
Understanding attackers’ behavior after gaining initial access can significantly enhance detection efforts. Here are three common indicators:
- Abnormal Login Behavior Attackers often use stolen credentials to access systems. Look for patterns such as:
- Logins from unusual geographic locations.Attempts to access accounts outside of regular hours.Multiple failed login attempts followed by a successful login.Logins from unfamiliar devices or simultaneous logins from different regions.
- Usage of Remote Desktop Protocol (RDP) RDP misuse is a hallmark of many ransomware attacks. Cybercriminals exploit open RDP ports to move laterally within networks or exfiltrate data. Brute-force attacks on RDP endpoints are also a common tactic.
Actionable Tip:- Restrict RDP access to trusted IPs.
- Enforce multi-factor authentication (MFA) for all remote access.
- Regularly audit RDP access logs for anomalies.
- Close unnecessary RDP ports and monitor for signs of brute-force attempts.
- Abnormal PowerShell Activity PowerShell, a tool commonly used by system administrators, is often exploited by attackers to execute malicious scripts. Techniques such as the execution of encoded scripts or use of “living-off-the-land” tools make it even more challenging to detect.Actionable Tip:
- Enable PowerShell logging via Group Policy or registry keys.
- Aggregate logs into a centralized storage system like a SIEM for analysis.
- Monitor logs for signs of unexpected or unauthorized script execution, such as encoded commands or unusually high activity.
Best Practices for Post-Compromise Detection
To strengthen your organization’s ability to detect and respond to threats, consider these best practices:
- Centralized Log Management: Use tools like SIEMs to aggregate and analyze logs across your environment.
- Behavioral Analytics: Leverage user behavior analytics (UBA) tools to detect atypical activity.
- Regular Audits and Testing: Conduct routine audits of system logs and test detection capabilities to ensure preparedness.
- Incident Response Planning: Develop and regularly update an incident response plan to outline specific steps for responding to detected threats.
- Threat Intelligence Integration: Incorporate feeds that highlight known attacker tactics, techniques, and procedures (TTPs) to enhance detection accuracy.
Ransomware attackers rely on stealth, but their activities often leave behind digital breadcrumbs. Organizations can turn these breadcrumbs into actionable intelligence by focusing on post-compromise detection. Prioritizing abnormal login behavior, RDP misuse, and PowerShell activity can mean the difference between detecting an attack early and limiting its impact versus falling victim to devastating ransomware.
Ready to dig into the findings? Read the full report here to explore comprehensive insights into ransomware trends, detection strategies, and effective defense measures.
Ben MartinMooney
Product Marketing Manager,
GuidePoint Security