| Alias: | Red_Spider |
| Strain: | Reverse strain |
| detected when: | |
| where: | |
| Classification: | COM and EXE infector, resident |
| Length: | 61 paragraph(s) |
Preconditions | |
| Operating System(s): | MS-DOS |
| Version/Release: | |
| Computer model(s): | PC's |
| Caroname: | Reverse.A |
Attributes | |
| Easy identification: | |
Type of Infection: | Appending, uses DOS file length to position virus. COMMAND.COM: The virus overwrites a constant data area of the file. Bootsector infection. Selfrec in memory: INT 21h/DCBAh => AX=ABCDh Selfrec on disk: File[12h..13h] {checksum in .EXE files} = ABCDh |
| Infection Technique: | |
| Infection Trigger: | Load&Exec, FileOpen, GetSetAttrib, RenameINFECTION_CRIT: Filelength >= 2000,COMlength < 63500,EXElength <= 512K,EXEloadSize = EXEfileSize,Filename <> "NCMAIN.EXE",File[2Ch..2Fh] <> "Sell" |
| Storage Media affected: | |
| Interrupts hooked: | INT 21h/4B00h, 21h/43h, 21h/56h, 21h/3Dh, 21h/DCBAh,23h (during infection), 24h (during infection) |
| Stealth: | |
| Tunneling/Selfprot: | |
| Oligo/Polymorphism: | |
| Encoding Method: | |
| Damage: | Transient: None Permanent: None |
| Damage Trigger: | Transient: None Permanent: None |
| Particularities: | shrinks the current MCB, and creates a new MCB in the released space - copying the original MCB marker. None Not displayed text: "Red Spider Virus created by Garfieldfrom Zielona Gora in Feb 1993","moc.dnammoc","exe.niamcn" (all encrypted) A regular fast infector with one point of interest:when infecting COMMAND.COM, the virus writes its bodystarting not at the end of the file but at a point3C0h bytes *back* from the end of the file, where mostversions of COMMAND have a bunch of zero bytes.Under DOSes such as DR-DOS 6.0, where COMMAND.COM isactually as misnamed .EXE file, such infection is abad idea. |
| Similarities: | |
Agents | |
| Countermeasures: | |
| Standard means: | |
Acknowledgements | |
| Location: | Virus Test Center, University Hamburg, FRG |
| Classification by: | Paul Ducklin |
| Documentation by: | Paul Ducklin |
| Date: | |
| Information Source: | Caroentry (autom.converter by S.Freitag) |
(c) 1996 Virus-Test-Center, University of Hamburg