Cyber Attack Symptoms

A cyber attack can compromise your computer's security even when advanced antivirus software is installed. While regular system scans provide protection, attackers use sophisticated techniques that may bypass detection. Recognizing the warning signs of an active attack is crucial for immediate response and damage control.

Understanding these symptoms helps identify potential breaches before significant damage occurs, allowing for prompt remediation actions.

Common Cyber Attack Symptoms

Process and Network Anomalies

• Unauthorized PowerShell activity − Unusual PowerShell processes running in Task Manager without user initiation indicate potential remote access or malware execution.

• Suspicious network connections − Connections established on ports 4444 or 445 without user knowledge (visible using netstat -ano command) suggest unauthorized remote access attempts.

• Firewall/Defender shutdown − Security software disabling automatically indicates a privilege escalation attack where attackers gain administrative control to disable defenses.

netstat -ano
# Check for unauthorized connections on ports 4444, 445

File and System Behavior Changes

• Malicious PDF processes − Unknown PDF files running in Task Manager may contain embedded malware or viruses designed to compromise system security.

• File encryption − Files suddenly becoming encrypted and inaccessible until payment is made indicates a ransomware attack.

• Unauthorized system control − Mouse movements, program selections, or automatic system functions without user input suggest remote control by attackers.

Network and Browser Indicators

• Persistent HTTP/HTTPS requests − Ongoing connections to ports 80 and 443 (visible through netstat or Wireshark) after closing browsers indicate port redirection attacks.

• Excessive UDP traffic − Large volumes of unwanted UDP requests detected by network monitoring tools suggest Distributed Denial of Service (DDoS) attempts.

• Browser redirection − Homepage changes or redirects to unknown websites indicate browser hijacking and potential system infiltration.

• Performance degradation − Slow video streaming, buffering issues, or delayed web page loading may indicate Wi-Fi piggybacking attacks where unauthorized users consume bandwidth.

• DNS setting changes − Modified router DNS configurations (detectable using F-Secure Router tool) suggest DNS hijacking attacks.

Immediate Response Measures

• Terminate malicious processes − Kill suspicious processes in Task Manager. Note that advanced attackers may hide malware within legitimate processes like explorer.exe using techniques such as prependmigrate=true.

• Enable comprehensive firewall protection − Activate Windows Firewall with updated definitions, blocking all ports except necessary ones (80, 443) for web traffic.

• Avoid suspicious content − Do not open unknown PDF files or URLs from untrusted sources, as these are common attack vectors.

• Implement network security − Install Intrusion Detection and Prevention Systems (IDPS) at router level and isolate sensitive servers in a DMZ (Demilitarized Zone).

Conclusion

Recognizing cyber attack symptoms through process monitoring, network analysis, and behavioral changes enables early detection and response. Implementing immediate countermeasures and maintaining robust security practices are essential for protecting against sophisticated cyber threats.