Skip to main content

Nygus

Classification

Category:

Malware

Type:

Virus

Aliases:

  • Nygus

Summary

Nygus is a resident file virus which infects both COM and EXE files.

Removal

Technical Details

When infected file is executed for the first time, virus will install itself in memory and reserves 1024 bytes for itself. At this time the virus will also hook interrupt 21h.

The int21 handler intercepts calls to DOS function 4B00h (loadexec). The read-only attribute is cleared if set, but not restored afterwards. Infection is only attempted if at least 1 cluster is available on the default drive. Files matching COMM*.*, MKS_*.*, COS_*.* or MKMM*.* are not infected. These files include some antivirus programs and DOS' command interpreter COMMAND.COM.

Virus infects all EXE files which are not already infected and are between 768 bytes and 192 kilobytes. Virus infects all uninfected COM files which are longer than 640 bytes. Virus contains an encrypted text message saying '(c)Nygus v2.0'. The text is not used anywhere by the virus.

There is one known 752 byte variant of this virus.

Protect your devices from malware with F‑Secure Total

Protecting your devices from malicious software is essential for maintaining online security. F‑Secure Total makes this easy, helping you to secure your devices in a brilliantly simple way.

  • Award‑winning antivirus and malware protection

  • Online browsing, banking, and shopping protection

  • 24/7 online identity and data breach monitoring

  • Unlimited VPN service to safe­guard your privacy

  • Password manager with private data protection

Choose how many devices you want to protect to get started.

  • Free customer support

  • Cancel anytime

  • The trial does not obligate you to buy the product

After 30 days your subscription will renew automatically for one year at €69.99.

More Support

Community

Ask questions in our Community.

User guides

Check the user guide for instructions.

Contact Support

Chat with with or call an agent.

Submit a Sample

Submit a file or URL for analysis.