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ValveSoftware / Source-1-Games

Source 1 based games such as TF2 and Counter-Strike: Source
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[TF2] Server crashing exploit making casual mode unplayable. #3231

Closed DarkRTA closed 4 years ago

DarkRTA commented 4 years ago

TF2 is currently plagued with bots that are crashing official servers after an attempted votekick. I have no details on how this server crashing exploit works so if anyone else has them please disclose them to Valve privately.

This is making casual mode literally unplayable and will kill the game entirely if not fixed soon.

There has also been a lot of discussion about this on the TF2 subreddit: https://www.reddit.com/r/tf2/comments/ftpw2m/addressing_the_cheater_in_the_room

Wosheereal commented 4 years ago

If i were to add to this. The exploit actually affects all source 1 games. It has something to do with the give_status command being spammed until the server can't handle it and dies.

joeyjumper94 commented 4 years ago

one of them is some how forced me to run +showroundinfo then -showroundinfo until i got kicked for 

Disconnect: #GameUI_Disconnect_TooManyCommands.

edit seems that spamming F1 to vote yes caused it

nosoop commented 4 years ago

The exploit's already out in the wild, and to my knowledge was previously exploited and subsequently patched on CS:GO.

It requires a modified client (cheat) to send a malformed packet. CLZSS::SafeUncompress() doesn't do any bounds checking on its position value to ensure it's within the output buffer.

nosoop commented 4 years ago

This exploit appears to be fixed (in TF2) as of today's update.

The engine was modified to use an updated version of CLZSS::SafeUncompress() backported from CS:GO, with checks to ensure that the (unsigned) offset isn't larger than the number of bytes uncompressed.

DarkRTA commented 4 years ago

This definitely appears to be fixed. Closing this.