From: SecuriTeam <support@securiteam.com.>
To: [email protected]
Date: 2 Nov 2005 09:30:56 +0200
Subject: [NEWS] Cisco IPS MC Malformed Configuration Download Vulnerability
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Cisco IPS MC Malformed Configuration Download Vulnerability
------------------------------------------------------------------------
SUMMARY
The CiscoWorks VPN/Security Management Solution (VMS) is a network
management application that includes Web-based tools for configuring,
monitoring, and troubleshooting VPNs, firewalls, network intrusion
detection systems (NIDSs), network intrusion prevention systems (NIPSs)
and host intrusion prevention systems (HIPSs). CiscoWorks VMS also
includes network device inventory, change audit, and software distribution
features.
An issue exists in one of the components of the Cisco Management Center
for IPS Sensors (IPS MC) v2.1 during the generation of the Cisco IOS IPS
(Intrusion Prevention System) configuration file that may result in some
signatures belonging to certain classes being disabled during the
configuration deployment process.
Cisco has made a free software patch available to address this
vulnerability for affected customers.
DETAILS
Affected Products:
Vulnerable Products:
* Cisco IOS IPS devices that have been configured by IPS MC v2.1.
Products Confirmed Not Vulnerable:
* Cisco IOS IPS devices that have NOT been configured by IPS MC v2.1.
This category includes Cisco IOS IPS devices that have been configured by
using any of the following methods:
o Cisco IDS MC (Management Center for IDS Sensors)
o Cisco SDM (Security Device Manager)
o Cisco IOS CLI (Command Line Interface)
* Any other Cisco IDS/IPS solution, configured by either Cisco IPS MC
v2.1, Cisco IDS MC (any version), Cisco SDM (any version) or by using the
Cisco IOS CLI. These include:
o Cisco IOS IDS
o Cisco PIX/ASA IDS
o Cisco IPS 4200 Series Sensors
o Cisco Catalyst 6500/7600 Series Intrusion Detection System (IDSM-2)
Module
o Cisco IDS Network Module (NM-CIDS-K9)
o Cisco ASA Advanced Inspection and Prevention (AIP) Security Services
Module
No other Cisco products are currently known to be affected by these
vulnerabilities.
Details:
Some Cisco routers running Cisco IOS include a feature called Cisco IOS
IPS. The Cisco IOS IPS acts as an in-line intrusion protection sensor,
watching packets and sessions as they flow through the router and scanning
each packet to match any of the Cisco IOS IPS signatures that have been
enabled on the device configuration. When it detects suspicious activity,
it responds before network security can be compromised and logs the event
through Cisco IOS syslog messages or Security Device Event Exchange
(SDEE). The network administrator can configure Cisco IOS IPS to choose
the appropriate response to various threats.
Customers can use multiple methods, including Cisco IPS MC, Cisco IDS MC,
Cisco SDM and the Cisco IOS CLI, to enable, disable and configure Cisco
IOS IPS signatures. Some signatures dealing with TCP or UDP traffic
analyze traffic destined to specific ports. Those ports are pre-configured
with default values, and some signatures might allow changes to the list
of ports to be monitored.
If the Cisco IOS IPS devices have been configured by using the Cisco IPS
MC v2.1, the Cisco IPS MC might download a configuration file to the
device that does not contain a value for the port field in one or more
signatures, resulting in the affected Cisco IOS IPS device disabling those
signatures. Only signatures using either the STRING.TCP or STRING.UDP
signature micro-engine (SME) are affected by this vulnerability.
Additionally, this behavior only happens if those signatures were enabled
and configured from the Cisco IPS MC GUI ; signatures belonging to the
STRING.TCP or STRING.UDP SMEs that were previously configured on the
device and imported into the Cisco IPS MC will not experience this issue.
The list of signatures currently loaded into a Cisco IOS IPS device and
their status can be obtained by executing the show ip ips signatures
command. The following abbreviated output shows signatures currently
loaded into the device, both enabled and disabled:
Router#show ip ips signatures
Builtin signatures are configured
Signatures were last loaded from flash:128MB.sdf
Cisco SDF release version 128MB.sdf v4
Trend SDF release version V0.0
*=Marked for Deletion Action=(A)larm,(D)rop,(R)eset Trait=AlarmTraits
MH=MinHits AI=AlarmInterval CT=ChokeThreshold
TI=ThrottleInterval AT=AlarmThrottle FA=FlipAddr
WF=WantFrag
Signature Micro-Engine: OTHER (4 sigs)
SigID:SubID On Action Sev Trait MH AI CT TI AT FA WF Version
----------- -- ------ ---- ----- ----- ----- ----- ----- -- -- -- -------
1201:0 Y A HIGH 0 0 0 30 15 FA N N 2.2.1.5
1202:0 Y A HIGH 0 0 0 100 15 FA N N 2.2.1.5
1203:0 Y A HIGH 0 0 0 30 15 FA N N 2.2.1.5
3050:0 Y A HIGH 0 0 0 0 15 FA N 1.0
Signature Micro-Engine: STRING.ICMP (1 sigs)
SigID:SubID On Action Sev Trait MH AI CT TI AT FA WF Version
----------- -- ------ ---- ----- ----- ----- ----- ----- -- -- -- -------
2156:0 Y A MED 0 0 0 0 15 FA N S54
Signature Micro-Engine: STRING.UDP (16 sigs)
SigID:SubID On Action Sev Trait MH AI CT TI AT FA WF Version
----------- -- ------ ---- ----- ----- ----- ----- ----- -- -- -- -------
4060:0 Y A MED 0 0 0 0 15 FA N S10
4060:1 Y A MED 0 0 0 0 15 FA N S173
4607:0 Y A HIGH 0 0 0 0 15 FA N S30
4607:1 Y A HIGH 0 0 0 0 15 FA N S30
4607:2 Y A HIGH 0 0 0 0 15 FA N S30
4607:3 Y A HIGH 0 0 0 0 15 FA N S30
4607:4 Y A HIGH 0 0 0 0 15 FA N S30
4608:0 N A HIGH 0 1 0 0 15 FA N S30
4608:1 Y A HIGH 0 1 0 0 15 FA N S30
4608:2 Y A HIGH 0 1 0 0 15 FA N S30
11000:0 N A LOW 0 0 0 0 15 FA N S37
11000:1 Y A LOW 0 0 0 0 15 FA N S37
11000:2 Y A LOW 0 0 0 0 15 FA N S136
11207:0 Y A INFO 0 0 0 0 15 FA N S139
11208:0 Y A INFO 0 0 0 0 15 FA N S139
11209:0 Y A INFO 0 0 0 0 15 FA N S139
Signature Micro-Engine: STRING.TCP (60 sigs)
SigID:SubID On Action Sev Trait MH AI CT TI AT FA WF Version
----------- -- ------ ---- ----- ----- ----- ----- ----- -- -- -- -------
3116:0 Y A HIGH 0 1 0 0 15 FA N S12
3117:0 N A LOW 0 1 0 0 15 FA N S13
3117:1 Y A LOW 0 1 0 0 15 FA N S13
3120:0 Y A LOW 0 1 0 0 15 FA N S13
3120:1 Y A LOW 0 1 0 0 15 FA N S13
3132:0 Y A HIGH 0 1 0 0 15 FA N S67
3132:1 Y A HIGH 0 1 0 0 15 FA N S67
3135:0 Y A HIGH 0 1 0 0 15 FA N S73
3137:1 Y A HIGH 0 1 0 0 15 FA N S83
3137:2 Y A HIGH 0 1 0 0 15 FA N S128
3141:0 Y A HIGH 0 1 0 0 15 FA N S94
3142:1 Y A HIGH 0 1 0 0 15 FA N S92
3152:0 Y A MED 0 1 0 0 15 FA N 2.1.1
3450:0 Y A LOW 0 1 0 0 15 FA N 1.0
5570:0 Y A R HIGH 0 1 0 0 15 FA N S185
5571:0 Y A R HIGH 0 1 0 0 15 FA N S185
9479:0 Y A HIGH 0 1 0 0 15 FA N S104
9480:0 Y A HIGH 0 1 0 0 15 FA N S104
9481:0 Y A HIGH 0 1 0 0 15 FA N S104
9482:0 Y A HIGH 0 1 0 0 15 FA N S104
9483:0 Y A HIGH 0 1 0 0 15 FA N S104
--More--
Any signature with a capital N under the 'On' column is DISABLED, while
any signature with a capital Y under the same column is ENABLED. In this
example, signatures 4608:0 and 11000:0 (belonging to the STRING.UDP SME),
and signature 3117:0 (belonging to the STRING.TCP SME) are listed as
disabled. For each signature listed as disabled in the output of the show
ip ips signatures command, a corresponding ip ips signature <SigID>
<SubsigID> disable command should be visible on the running configuration.
This is an example of the show running-configuration command, using a
filter to only display configuration lines belonging to signatures that
have been disabled:
Router#show running-config | include ip ips signature .* disable
ip ips signature 11000 0 disable
ip ips signature 4608 0 disable
ip ips signature 3117 0 disable
Router#
Impact:
While this is not a vulnerability in the Cisco IOS IPS code itself, in the
processing performed by Cisco IOS IPS on traffic traversing the device, or
in the Cisco IPS MC v2.1, this vulnerability might result in an incomplete
analysis of network traffic traversing the Cisco IOS IPS device, which
could allow some attacks to go unnoticed.
Software Versions and Fixes:
When considering software upgrades, please also consult
<http://www.cisco.com/en/US/products/products_security_advisories_listing.html>; http://www.cisco.com/en/US/products/products_security_advisories_listing.html and any subsequent advisories to determine exposure and a complete upgrade solution.
In all cases, customers should exercise caution to be certain the devices
to be upgraded contain sufficient memory and that current hardware and
software configurations will continue to be supported properly by the new
release. If the information is not clear, contact the Cisco Technical
Assistance Center ("TAC") for assistance.
Cisco has developed a software fix for this vulnerability. Once the fix is
applied to a VMS server running IPS MC v2.1, the IPS MC will correctly
populate the port field attached to a signature using either the
STRING.TCP or STRING.UDP SME. Additional steps will be required to be
performed. Please read the README file published together with the
software fix.
In order to obtain this software fix, customers should access the VMS
Software download page for IDS MC and IPS MC, available at
<http://www.cisco.com/pcgi-bin/tablebuild.pl/mgmt-ctr-ids-app>;
http://www.cisco.com/pcgi-bin/tablebuild.pl/mgmt-ctr-ids-app. The fix
consists of the following three files:
* idsmdc2.1.0-win-CSCsc336961.tar - this file contains the fix itself for
IPS MC v2.1 running on the Windows operating system.
* CSCOids2.1.0-sol-CSCsc336961.tar - this file contains the fix itself
for IPS MC v2.1 running on the Solaris operating system.
* CSCsc33696-README.txt - this file contains instructions on how to apply
the software fix to an affected IPS MC v2.1 installation (either Windows
or Solaris) and any needed pre and post installation tasks to be carried
out by the user.
ADDITIONAL INFORMATION
The information has been provided by <mailto:psirt@cisco.com.> Cisco
Systems Product Security Incident Response Team.
The original article can be found at:
<http://www.cisco.com/warp/public/707/cisco-sa-20051101-ipsmc.shtml>;
http://www.cisco.com/warp/public/707/cisco-sa-20051101-ipsmc.shtml
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