Brett Hutley ([EMAIL PROTECTED]) wrote on 2003-11-26 at 11:32:
Folks, does anyone know why predictable process IDs are considered harmful?
Predictable process IDs can be used as a vector to attack programs
vulnerable to race conditions in /tmp file creation, in case those
programs use their PID to create a file, meaning you could possibly
create one (or, for "practical" uses, more often a link or a named pipe)
first.
Programs which uses the following pseudo-code are also vulnerable:
srand (getppid ());
because the sequence of the so-called rand()om numbers is predictible. (Arguably, calling srand() passing a xor of your PID and the current time is no better. See perldoc -f srand for a discussion on this, I'm getting offtopic.)
Hmmm... so it's more a case of badly written program using the process ID in an insecure way causes the vulnerability rather than a predictable process ID causing a vulnerability itself?
Thus, I remember a really weird situation where predictable PIDs were used to compromise security, it was discussed on BugTraq a while ago, but I couldn't find a track of it in my BT archive... anyone?
-- Brett Hutley [MAppFin,CISSP,SANS GCIH] mailto:[EMAIL PROTECTED] http://hutley.net/brett
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