I tried this and it seemed to not work on my Linux system. I'm running both RedHat 7.1 and 6.0 -----Original Message----- From: Sabau Daniel [mailto:dravenat_private] Sent: Monday, April 22, 2002 2:44 AM To: vuln-devat_private Cc: focus-linuxat_private Subject: /lib/ld-2.2.4.so or: lrwxrwxrwx 1 root root 11 Apr 15 12:01 /lib/ld-linux.so.2 -> ld-2.2.4.so This file gives users the ability of running binaries on witch the user doesn't have the permission to execute, it is enough to have read ability on the file in order to execute it: -rwxr-xr-- 1 root root 45948 Aug 9 2001 /bin/ls but using the /lib/ld-2.2.4.so file i can execute the ls command: [08:51:36][draven@Zero:~]:$/lib/ld-2.2.4.so /bin/ls / bin bzImage bzImage3 bzImage5 dev home lib mnt proc sbin usr boot bzImage2 bzImage4 bzImage6 etc initrd misc opt root tmp var i do not have root preveleges on this account: [08:51:38][draven@Zero:~]:$id uid=1000(draven) gid=10(wheel) groups=10(wheel),16(trust) The most interesting part is running binaries on partitions mounted with noexec, lets take this partition: /dev/sda9 on /home/friends type ext2 (rw,noexec,nosuid,nodev,usrquota,grpquota) i've created a shell acount with the home directory: [mjj@Zero mjj]$ pwd /home/friends/mjj and wrote this C code in a file test.c #include <stdio.h> void main(void) { printf ("Test"); } i've compiled it & tryed to run: [mjj@Zero mjj]$ ./a.out bash: ./a.out: Permission denied but when i try to run it with /lib/ld-2.2.4.so: [mjj@Zero mjj]$ /lib/ld-2.2.4.so ./a.out Test the important thing is to include a full path in the binary name to be able to execute it. in the same way i've managed to run the ptrace exploit on a nosuid partition i'm running a 2.4.18 kernel with grsecurity-1.9.4 patch on a Red Hat Linux 7.2 box, but i've succeded running this file on different linux boxes and i've been succesfull, please if anyone know how to eliminate this hole in my security give me a replay. If i try to change the mode on /lib/ls-2.2.4.so to 700, the users will not be able to login on my linux box, so this is not a solution:) 10x, Dan Sabau -- "From all the things I lost, My mind, I miss the most!" echo '16i[q]sa[ln0=aln100%Pln100/snlbx]sb20293A2058554E494Csnlbxq'|dc
This archive was generated by hypermail 2b30 : Wed Apr 24 2002 - 13:20:10 PDT