Groove Virus

Alias:
Strain:MtE-based
detected when:USA
where:June 1992
Classification:Polymorphic, memory-resident program (COM and EXE, appending
Length:1. In RAM: 140 paragraphs; 2. on file: variable on disk due to MtE.

Preconditions

Operating System(s):MS/PC DOS
Version/Release:3.0+ ???
Computer model(s):All 80x86-based PCs
Caroname:MtE.Groove

Attributes

Easy identification:Programs stop running as expected if at all.

Type of Infection:

COM & EXE programs (not based on extension)

Infection Technique:
Infection Trigger:Execution using INT 21h function 4B.
Storage Media affected:All (diskettes,,hard disk)
Interrupts hooked:INT 21h, INT 24h
Stealth:
Tunneling/Selfprot:
Oligo/Polymorphism:
Encoding Method:
Damage:Transient damage: the following message will either be displayed after 12:30 midnight based on the tick count returned by INT 1Ah on systems with a RTC, or it is displayed every time when a file is infected: "Dont wory, you are not alone at this hour... This Virus is NOT dedicated to Sara its dedicated to her Groove (...Thats my name) This virus is only a test virus therefore be ready for my Next Test .." This message is not readable in most mutations due to encryption. Permanent damage: Virus will delete the following files upon activation: C:\NAV_._NO C:\NOVIRCVR.CTS C:\NOVIPERF.DAT C:\CPAV\CHKLIST.CPS C:\TOOLKIT\FILES.LST C:\UNTOUCH\UT.UT1 C:\UNTOUCH\UT.UT2
Damage Trigger:Execution of an infected file
Particularities:Virus does not check file extension to determine its type, but rather checks for "MZ" or "ZM" at the start of a file and assumes EXE-type if a match is found; otherwise, it infects as a COM-type file. Infected files will not run properly.
Similarities:---

Agents

Countermeasures:Same as above, but all antivirals that can detect MtE-based viruses 100% of the time should be effective.
Standard means:Delete infected files and restore clean copies.

Acknowledgements

Location:Baltimore, MD, U.S.A.
Classification by:Tarkan Yetiser, VDS Advanced Research Group
Documentation by:Tarkan Yetiser
Date:29-June-1992
Information Source:---

(c) 1996 Virus-Test-Center, University of Hamburg