| Alias: | |
| Strain: | |
| detected when: | |
| where: | |
| Classification: | Other!??? , resident |
| Length: | 896 |
Preconditions | |
| Operating System(s): | MS-DOS |
| Version/Release: | .AVR-based scanners |
| Computer model(s): | PC's |
| Caroname: | Horns |
Attributes | |
| Easy identification: | |
Type of Infection: | The virus appends itself to the files Selfrec in memory: INT_21;AX=44A0 -> AH=FF Selfrec on disk: File[0x48] = 0xE9 |
| Infection Technique: | |
| Infection Trigger: | (Open for Read-Only + Close) and FileName[0..1]=='C:'and FileExt=='.AVR' and File[0x48] != 0xE9 andFile[0x41..0x43]==0x000100 and (File[0x3c..0x3d] & 0xf)==0 |
| Storage Media affected: | |
| Interrupts hooked: | 21/3D00, 21/3E, 21/44A0 |
| Stealth: | |
| Tunneling/Selfprot: | |
| Oligo/Polymorphism: | - |
| Encoding Method: | |
| Damage: | Transient: An infected AVR module will report correct result(whether a file being scanned is infected or not)with a probability 1/4. In 3/4 of cases it will report"not infected" regardless on actual state.IN FACT, due to a bug, an infected .AVR will alwaysreport "not infected" (C-flag will always be cleared onreturn) Permanent: |
| Damage Trigger: | Transient: (BIOS_TIMER_TICKS & 03) != 0 Permanent: |
| Particularities: | The virus resides above the last MCB Not displayed text: "[Horns Of Jericho (c) 92 Crom-Cruach/Trident]" A victim file name should be of 'C:*.AVR' form - upper caseletters only. MS-DOS 5.0 commands COPY and TYPE do notwork - perhaps, they do not use int 21/3D00 to open a file. |
| Similarities: | |
Agents | |
| Countermeasures: | |
| Standard means: | |
Acknowledgements | |
| Location: | Virus Test Center, University Hamburg, FRG |
| Classification by: | Dmitry O. Gryaznov |
| Documentation by: | Dmitry O. Gryaznov |
| Date: | 1993-07-21 |
| Information Source: | Caroentry (autom.converter by S.Freitag) |
(c) 1996 Virus-Test-Center, University of Hamburg