Type File virus
Date Discovered 2000.02.23
Place of Origin
Source Language
Platform Linux
File Type(s) ELF
Infection Length
Reported Costs

Telf or Obsidian is a family of viruses for Linux. Most variants of this virus refuse to infect other files if the user is logged in as root, instead scolding them for running the file as root and exiting.

Table of Contents


When Telf is executed, it searches for all ELF executables the user executing it has permissions to write to. If the user is running the virus as root, it does not infect anything, instead displaying the message "Hell no! Do not run this as root!".


The Telf family includes 5 known variants. Their sizes are particularly notable, ranging from Telf.E, which is only 8,000 bytes to Telf.B, which is 211,140 bytes.

Telf.E infects even when the user is logged in as root.


Sophos Antivirus, ELF/Obsidian-B.

Jason C. Leach. [Leaf-user Potential virus in IPsec pre 1.5.] 2002.02.12

Sophos Antivirus. ELF/Obsidian-E.

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