Monday, 19 October 2015

IPS Configuration Review: Tipping Point

This article presents some of the common checkpoints when reviewing Tipping Point IPS for an enterprise. Although, the points discussed could be configured/mis-configured for any IPS, this is not an exhaustive list.
For the benefit of the reader, TIPPING POINT
“protects your network by scanning, detecting, and responding to network traffic according to the filters, action sets, and global settings maintained on each device by a client. Each device provides intrusion prevention for your network according to the amount of network connections and hardware capabilities”

The primary set up of IPS in an organization would consist of the following:
    IPS Devices & Local Client
2      Core Controller
3      Security Management System (SMS server and client)
A visual depiction could be found as shown. This roughly depicts the overall architecture in a typical set up for an organization’s network.

Figure 1IPS in Network Architecture
Source: Tipping Point LSM User Guide

 Some of the common points to review would consist of the below:
1)      Filters & Profiles
This setting is of utmost importance in any IPS/IDS and is worth investing more time in. These filters will eventually set the rules for what is allowed and not allowed into or out of the network.
First consideration when reviewing filters is to evaluate the ‘Security profiles’ set in the IPS. The admin would generally divide the complete network into meaning full network segments. These segments would be allowed a set of protocols to communicate across.
IPS > Security Profiles
Each of these profiles would give Digital vaccine coverage to these segments.
There are other profiles such as the Traffic management profiles that help monitor network traffic into and out of these segments and can be tuned to thresholds to avoid network congestion. Unless, your network is small or medium sized, these must be defined set to optimum values.
Review Filters:
TIPPING POINT defines 3 kinds of filters:
  1. Application Filters
  2. Infrastructure Filters
  3. Performance Filters

The search features comes in handy and you can pick and select the suspicious or ‘insecure’ rules from mapped to the respective profiles as shown below:
 Figure 2 Profile Menu and search criteria

A.      Review the above in general to see what’s enabled and what’s disabled. You may check with team if there are specific reasons for suppressing some of the filters.
B.      Review these filters to see if a recommended filter is disabled and check with the team on the reasons why; applies to the Action settings for the filters as well. The filters can be viewed by selecting:
IPS > Security Profiles > View all filters
C.      Filter settings are used to override the global settings for individual filters within a category group : Check for exceptions here and ask if this went through change management; or for appropriate business justification for this.
D.      For DDoS filters check the below:
  •  Action taken
  •  Threshold for the maximum number of SYN connection requests allowed per second

E.       Preferences : It is a good idea to get a lot of system related parameters that have been set such as timeout, congestion threshold
F.       Unlike in case of firewalls, everything is set to ANY - ANY by default here. This means that All communication or traffic sent to and from Any port will be inspected as per the filters.

Any realistic network would require some exceptions though. This is done by creating ‘filter-level settings and overriding the global ‘Defaults’. Do check the filter level settings to verify what’s allowed and why? More often than not this would have  been a temporary requirement and should be reset once the task is done.

Below is an example of some filters that have been set to permit exploit signatures and vulnerabilities which are critical severity.

Figure 3 Action set to permit/permit-notify for critical exploits

In another example, action set was ‘disabled’ for some critical exploits and mapped to certain profiles.

Figure 4 Action Set disabled

While some of these may not be relevant issues, others would be. It would be worth noticing which signatures are marked for ‘Exception’, ‘locked’, ‘AFC’, ‘State’ and so on..
 Figure 5 Critical filters set to Permit

As is obvious, for rest of the interface, explanations are self-explanatory along with CVEs provided for further analysis.
In the same way other filters should be looked into such as reputation and DDoS filters.
Note: If the action for the filter is set to Recommended and you do not change it, the filter may remain disabled even when you select the Enabled check box. This happens when the recommended setting for the filter state is Disabled. To enable a filter with this setting, you must change the action from Recommended to another option.

2)      System Settings & Update
Managing an SMS system along with the various IPS devices in the network can be a task.
As a reviewer however, the system settings are relatively straightforward to check for any issues. A mini cheat sheet can help in a quick review.
a.       Check if the below are latest or up to date:
                 i.      Versions of the TOS
                ii.      The Digital Vaccine
                iii.      IP Reputation package

b.      Automatic updates are enabled for DV or a regular schedule is followed : System > Update > Auto DV Update

 Figure 6 DV set to Automatic update

c.       When was the system last updated
d.      Check with the team if the device is ready for a roll back if needed. Has this been tested
e.      Have system snapshots been taken
f.        In case of an LSM, check to see how the system is being managed; Has a secure management port been set, if and for which subnets has management routing been enabled and why, time options set, routing for SMS, etc..
g.       Has the system been integrated with an Email server? If yes you need to check the contacts, kind of filters enabled for alerting and is any critical filters has been left out.
Paths to look for: System > Update > Install Package
Review the mode of Administration to the system to check –
a.       How many users have been created and with what privileges. Primarily three types of users- Operator, Admin and super user.
b.      Password policy while setting user password for the device- check to see if this is Level 2. Any less can be reported. Match with client’s password policy
c.       Check for other miscellaneous thins such as timeouts, page refresh, password expiration, lock outs and so on..
Paths to look for: Authentication > Preferences

                                         Figure 7 Account settings

Figure 8 Device Configuration

3)      Logging & Alerting
There are many instances during the communication when we would configure events to be recorded for suspicious activities or further inspections. This could be classified depending on the actions taken on the traffic.

One of the table shows the how this is done in TIPPING POINT > Profiles > Action Sets
 Figure 9 None of the actions are marked for Syslog

  • A quick run through the logs should give some idea about the issues. Review the logs to check for unexpected activities and attacks. Check with the team to see if these have been handled.
  • It’s also a good idea to verify what kind of events are being logged and mark those that have been missed.
  • Check the ‘Trace’ events in particular
  • Log Storage: verify if and for how long are the logs stored and where; the security of the logs and if any monitoring is done on those. Look for the presence of SIEM and major incidents if any.

Alerts: Check to see which contacts are to be emailed for alerts and if the right kind of events along with the appropriate set of details are mailed to the rightful owner.

Figure 10 Format of Audit Log Parameters in the IPS

Note: Only Administrator and Super-user level users can reset the system log. Only Super user level users can reset the audit log. All can view the logs.

4)      Traffic Management & Streams
Traffic management filters are the ones that allow or deny access in and out of segments over predefined protocols. Additionally they allow the user to ‘Rate Limit’ the traffic based of certain criteria. 
Check this to see if the organization utilizes these to rate limit traffic for DoS prone protocols, restrict UDP traffic, condition egress filtering and so on. Without these advanced filters being set, an IPS may just be reduced to a smarter firewall. An example of this shown below:
   Figure 11 Traffic management filters not set

These can be of the below types :
  •  Blocked streams
  •  Rate-Limited streams
  •  Quarantined
  •  Trusted

These are all as the name suggests and can be verified at the path below:
Events > Managed Streams > Blocked Streams, Rate Limited Streams and so on..
If these have not been set sufficiently, then traffic amplification based attacks might go undetected or cause unavailability. Moreover, this is one of the features that differentiates IPS over Firewall and should be used effectively.

5)      Availability & Reporting
The IPS can be run on various High availability modes. Check to see if any and which ones are enabled, is that suited for the architecture and redundancy expected from the IPS:
§  Intrinsic Network HA (INHA) for individual device deployment. > Layer-2 Fallback – default allow ALL
§  Transparent High Availability (TRHA) - for devices deployed in a redundant configuration where one device takes over for the other in the event of system failure.
§  Zero-Power High Availability, which provides high availability through an external device or through a Smart ZPHA module.
System > High Availability
Check to see if any of these are set and if yes if it suits the network architecture and respective IPS placement. Below is a setting that shows an example of High Availability setup for the device.
 Figure 12 HA status as reflected in device configuration

  Figure 13 Devices > Member Summary > HA

 Figure 14 ‘Back Ups’ state for a sample IPS

Note: Look for the REDs in the configuration settings. Most of the times these are obvious mis-configuration that might shell out some good findings.

Reporting: The IPS provides a lot of options for reporting on a daily, weekly and monthly basis. The reviews and checks conducted above should give a fare idea as to what type of reports are necessary for the organization in a short, medium and long term. The important ones to look for are as follows :
  • Attack reports by the filters and action sets
  • Rate Limit & DDoS reports for traffic streams

Path to look into : IPS > Reports 

Verifying the above would give you an overall idea of what kind of traffic is coming in and going out, network is prone to what kind connections and attack scenarios, if there are and how many attempts to overload the network bandwidth and if the network is capable to face it. These should cross checked for monitoring by the internal team and actions taken if any.

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