F1-337

Alias:
Strain:-
detected when:
where:
Classification:COM-infector, resident
Length:54 paragraph(s)

Preconditions

Operating System(s):MS-DOS
Version/Release:All models
Computer model(s):PC's
Caroname:F1-337

Attributes

Easy identification:

Type of Infection:

The virus prepends itself to the files Selfrec in memory: Int21;AH=F1 exits into host program Selfrec on disk: File[0] == 0F1B4h (mov ah,0F1h)

Infection Technique:
Infection Trigger:(Load || Open || Ext_Open/Create) && Filename[namelength-6]!= "ND" && Filesize < 64768
Storage Media affected:
Interrupts hooked:21/F1, 21/6C, 21/4B, 21/3D, 24
Stealth:
Tunneling/Selfprot:
Oligo/Polymorphism:-
Encoding Method:
Damage:Transient: - Permanent: -
Damage Trigger:Transient: - Permanent: -
Particularities:The virus resides as a TSR Int24 vector is not restored after infecting a file The Int21;AH=6C handling assumes the filename pointer is in DXbut it is really in SI. The filename checking is for "*CO?" andtherefore some wrong filenames will be selected.
Similarities:

Agents

Countermeasures:
Standard means:

Acknowledgements

Location:Virus Test Center, University Hamburg, FRG
Classification by:Adam David, Frisk Software International
Documentation by:Adam David, Frisk Software International
Date:28.7.93
Information Source:Caroentry (autom.converter by S.Freitag)

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