Avenger

Avenger was a computer virus conceived by Jay Felger, who also developed it along with his assistant Chloe and Samantha Carter. It was designed to scramble the symbols of a DHD, making it impossible to dial another Stargate. The Stargate on P5S-117 was chosen to test the virus because the planet was one of Ba'al's major naquadah mining sites. The test was successful, however Ba'al discovered the virus and modified so it would spread throughout the entire Stargate network via the correlative update system. With the entire network down, he gained the advantage against the other Goa'uld by having the largest fleet. Earth's Stargate was one of few still functional since it did not use a DHD. This allowed Felger and Carter to travel to P5S-117 in hopes to fix the problem. Felger modified his anti-virus and neutralized the new version of Avenger along with adding a patch so this would never happen again.