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Network Scanning: Concerns and Countermeasures


 

Network Scanning Concerns and Countermeasures

Daniel Saucier (Student of the InfoSec Industry, March 2012) – Network vulnerability scanning can not be more important than it is, right now in this day and age of internet computing. As technology grows the architectures are not catching up quite as fast as most would like. This article written below assumes you have basic networking knowledge, and assumes no responsibility for actions taken from this article. It’s sole purpose is to educate the savvy portion of the internet community with different protection types and threat preventive measures for today’s networking environments.

Different IP network scanning methods allow you to test and effectively identify vulnerable network components. Here is a list of effective scanning techniques and there applications: These options can be found in most advanced configuration options on most downloadable network scanners.

ICMP scanning and Probing:

>| By launching an ICMP ping sweep, you can effectively identified poorly protected hosts ( as security conscious administrator such as myself, filter inbound ICMP messages) and perform a degree of OS fingerprinting and reconnaissance by analyzing responses to the ICMP probe.

Half-open SYN flag TCP port scanning:

>| A SYN port scan is often the most effective type of port scan to launch directly against a target IP network space. SYN scanning is very fast, which allows large networks to be scanned rather quickly.

Inverse TCP port scanning:

>| Inverse scanning types (particularly FIN, XMAS, and NULL) take advantage of idiosyncrasies in certain TCP/IP stack implementations. This scanning type is not useful for large networks. Use this scan type for testing individual host or small network segments‘ security. Make sure your code is as up to date as possible and apply any manual workarounds to protect gear from this type of scan. Some if not all of these type of scans identify weak components because of the cost of business.

Third-party TCP port scanning:

>| Using a combination of vulnerable network components and TCP spoofing, third-party TCP port scans can be effectively launched. Scanning in this fashion has two benenfits: hiding the true source of the TCP scan and assessing the filters and levels of trust between hosts. Although time-consuming to undertake, this can be proved to be very effective when applied correctly.

UDP port scanning:

>| Identifying accessible UDP services can be undertaken easily, only if ICMP type 3 Code 3 (“Destination port unreachable”) messages are allowed back through filtering mechanisms that protect target systems. UDP services can sometimes be used to gather useful data or directly compromise hosts (the DNS, SNMP, TFTP, and BOOTP services in particular). Make sure you are locking these down!!

IDS evasion and filter circumvention:

>| Intrusion detection systems and other security mechanisms can be rendered ineffective by using multiple spoofed decoy hosts when scanning or by fragmenting probe packets using Nmap or fragroute. Filters such as firewalls, routers, and even software (IPsec) can sometimes be bypassed using specific source TCP or UDP port, source routing, or stateful attacks.

Using the different scanning methods mentioned above you can harden you network pretty well, however. Change is always a factor, what if you need to undertake a major network overhaul and start exposing different types of protocols to the network. The following list will help you when considering modifications to your components and minimize risk of re-exposing vulnerable services.

>| This list could be used as a baseline, guideline in some cases on any network configuration.

  1. Filter inbound ICMP message types at the border, or perimeter if you DMZ any servers on any routers and firewalls. This will force an attackers to use full-blown out TCP scans against all of your IP addresses to map effectively.
  2. Filter all outbound ICMP type 3 “unreachable” messages at the edge routers and firewalls to prevent UDP port scanning and firewalking from being effective. Firewalking – process of identifying firewalls in the scanning enumerations
  3. Consider configuring Internet firewalls so they can identify ports scans and throttle the connections accordingly. You can configure such as Check Point, NetScreen, and Watchguard appliances to name a few to prevent fast port scans and SYN floods from being launched against your network. However, this can back fire if the attacker is using a spoofed source address, resulting in DoS. PortSentry as an Open Source option is pretty effective as well in identifying scanns against your network.
  4. Asses the way that your network firewall or IDS devices handle fragmented IP packets by using tools such as fragtest and fragroute. Such devices can be taken down by being flooded with high volumes of fragments being processed. Bring your findings to the vendors attention……
  5. Ensure that your routing and filtering appliances (both routers and firewalls) can’t be bypassed using specific source ports or source routing techniques.
  6. If you run FTP services; ensure that your firewalls aren’t vulnerable to stateful circumvention attacks relating to malformed PORT and PASV commands
  7. If a commercial firewall is being used, ensure the following:
  • Latest code is installed, consider replacement is you can not comply
  • Antispoofing rules have been correctly defined so that the device doesn’t accept packets with private spoofed source addresses on its external interfaces

8.  Investigate the use of reverse proxy services if high security is a must. Fragments and malforms are not getting  by these guys, thus mitigating low level recon.

Wrapping up this article I would like to mention; be aware of your own network configurations and its publicly accessible ports by launching TCP and UDP port scans along with ICMP probes against your own IP address space. It really is surprising how many companies large and small still do not undertake proper scanning exercises.

Happy Hardening!

-DS

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NSA Addresses Mobile Security


A national Security Agency (NSA) pilot program aims to model secure classified communications over commercial mobile devices. However, the NSA has found that off-the-shelf products are inconsistent in their implementation of the standards and protocol that NSA requires. The agency would prefer not to have to be tied to one platform, but for the time being, they have no choice.

The standards and protocols exist to provide the security that NSA requires, but they are not being implemented consistently by vendors, Margaret Salter, a technical director in NSA’s Information Assurance Directorate, said Feb. 29 at the RSA Conference.

The agency went shopping with a list of requirements for encryption for the voice channel and for the Session Initiation protocol. “We couldn’t buy one” that met all the requirements, Salter said. “We could pay someone to make it, but that wasn’t the plan.”

More Herehttp://gcn.com/articles/2012/02/29/rsa-10-nsa-secure-android-phones.aspx

http://www.cio.com/article/701252/National_Security_Agency_Defines_Smartphone_Strategy_Think_Android_Maybe_


Cisco Security Advisory: Multiple Vulnerabilities in Cisco Wireless LAN Controllers


Cisco WLCs and Cisco WiSMs are responsible for system-wide wireless
LAN functions, such as security policies, intrusion prevention, RF
management, quality of service (QoS), and mobility.

These devices communicate with controller-based access points over any Layer 2 (Ethernet) or Layer 3 (IP) infrastructure using the Lightweight Access Point Protocol (LWAPP) and the Control and Provisioning of Wireless Access Points (CAPWAP) protocol.

The Cisco Wireless LAN Controller (WLC) product family is affected by
the following vulnerabilities:

* Cisco Wireless LAN Controllers HTTP Denial of Service Vulnerability
* Cisco Wireless LAN Controllers IPv6 Denial of Service Vulnerability
* Cisco Wireless LAN Controllers WebAuth Denial of Service Vulnerability
* Cisco Wireless LAN Controllers Unauthorized Access Vulnerability

Cisco has released free software updates that address these vulnerabilities. Workarounds are available that mitigate some of these vulnerabilities.

This advisory is available at the following link:
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20120229-wlc

Affected Products

The Cisco WLC product family is affected by multiple vulnerabilities. Affected versions of Cisco ASA Software vary depending on the specific vulnerability.

Vulnerable Products

Each of the following products is affected by at least one of the vulnerabilities covered in this Security Advisory:

* Cisco 2000 Series WLC
* Cisco 2100 Series WLC
* Cisco 2500 Series WLC
* Cisco 4100 Series WLC
* Cisco 4400 Series WLC
* Cisco 5500 Series WLC
* Cisco 500 Series Wireless Express Mobility Controllers
* Cisco Wireless Services Modules (WiSM)
* Cisco Wireless Services Modules version 2 (WiSM version 2)
* Cisco NME-AIR-WLC Modules for Integrated Services Routers (ISRs)
* Cisco NM-AIR-WLC Modules for Integrated Services Routers (ISRs)
* Cisco Catalyst 3750G Integrated WLCs
* Cisco Flex 7500 Series Cloud Controllers

Measures to mitigate these risks can be found here: http://tools.cisco.com/security/center/content/CiscoAppliedMitigationBulletin/cisco-amb-20120229-wlc


BYOD Control: Aruba brings it together with ClearPass


Aruba Delivers BYOD Control with ClearPass

The bring-your-own-device (BYOD) era is booming, while BYOD delivers some freedom to users and is great don’t get me wrong, however. It is still absolutely critical that companies reachthe same degree of protection,  and control that corporate owned devices also receive to these devices. It has to be thought of as a wired device, in my opinion.

Networking vendor Aruba is now debuting a solution for BYOD, built on Linux and leveraging the open source FreeRADIUS access controlsolution to help return control to enterprises.

English: offical logo of Aruba Networks

“ClearPass provides a networking solution for BYOD to address all of the majoroperating systems and any networking vendor’s network architecture,” Robert Fenstermacher, director of Product Marketing at Aruba, told InternetNews.com. “It can act as a single point of policy control across all wired, wireless and remote infrastructure for a global organization.”

More from ENP: http://www.enterprisenetworkingplanet.com/netsysm/aruba-delivers-byod-control-with-clearpass.html


Apple: Aims to Flick the Privacy Flea


Apple Will Require Apps to Obtain User Permission Before Accessing Contact Data

US legislators sent a letter to Apple CEO Tim Cook asking why the company does not require iOS developers to obtain permission from users before apps download users’ contacts. The inquiry follows close behind news that the Path app downloaded users’ address books without their permission. Apple has responded to the question with a promise to change that policy so apps requiring use of address book data request that information explicitly.

apps

*More on this story here:

*More on this story here:

[Editor’s Comment  (SANs.org):

“I wonder if they will be in time to avoid a major disaster. I was surprised to read on slashdot that your data was safer on unapproved apps for jailbroken iPhones than on approved apps from Apple’s store”:

http://apple.slashdot.org/story/12/02/15/0036242/unauthorized-ios-apps-leak-private-data-less-than-approved-ones]

 

***Back story on NetsecurityIT.com:

  1. https://netsecurityit.wordpress.com/2012/02/09/path-ios-app-stores-address-books-on-its-servers/
  2. https://netsecurityit.wordpress.com/2012/02/09/update-path-apologizes-for-storing-address-books-on-its-servers/

Android: Malware Magnet


In the last seven months of 2011, malware targeting the Android platform jumped 3,325 percent!

According to Juniper Networks‘ Mobile Threat Report, malware targeting the Android OS grew by 3,325 percent in the last seven months of 2011.

“Android malware accounted for about 46.7 percent of unique malware samples that targeted mobile platforms, followed by 41 percent for Java Mobile Edition,” writes eWeek’s Fahmida Y. Rashid.

Android System architecture

Android System Architecture

“The explosion in Android malware is a direct result of the platform’s diverse and open marketplace where developers are free to post their apps as well as growing market share, according to Juniper,” Rashid writes. “Google‘s market share in the mobile space, at 46.9 percent, is statistically the same as the proportion of Android malware detected by Juniper.”

 

Read More: 2011 Android Report: Malware

 

 

 


5 Steps for analyzing your WLAN


Assessing Your Wireless Network Security

Wireless network penetration testing—using tools and processes to scan the network environment for vulnerabilities—helps refine an enterprise’s security policy, identify vulnerabilities, and ensure that the security implementation actually provides the protection that the enterprise requires and expects. Regularly performing penetration tests helps enterprises uncover WLAN network security weaknesses that can lead to data or equipment being compromised or
destroyed by exploits (attacks on a network, usually by “exploiting” a vulnerability of the system),Trojans (viruses), denial of service attacks, and other intrusions.

Here is a great article I was reading on Cisco blogs and found it useful to post. Enjoy!

5 Steps for Assessing Your Wireless Network Security

Sampa Choudhuri – Network security is a never-ending task; it requires ongoing vigilance. Securing your wireless network can be particularly tricky because unauthorized users can quietly sneak onto your network, unseen and possibly undetected. To keep your WLAN secure, it’s important to stay on top of new wireless vulnerabilities. By regularly performing a vulnerability assessment on your wireless network, you can identify and close any security holes before a hacker can slip through them.

With a WLAN vulnerability assessment, you’re figuring out what your wireless network looks like to the outside world on the Internet. Is there an easy way in to your network? Can unauthorized devices attach themselves to your network? A WLAN vulnerability assessment can answer these questions—and more.

Teaser:

1. Discover wireless devices on your network. You need to know everything about each wireless device that accesses your network, including wireless routers and wireless access points(WAPs) as well as laptops and other mobile devices. The scanner will look for active traffic in both the 2.4GHz and 5GHz bands of your 802.11n wireless network. Then, document all the data you collect from the scanner about the wireless devices on your network, including each device’s location and owner.

English: A Linksys wireless-G router.

2. Hunt down rogue devices. Rogue devices are wireless devices, such as an access point, that should not be on your network. They should be considered dangerous to your network security and dealt with right away. Take your list of devices from the previous step and compare it to your known inventory of devices. Any equipment you don’t recognize should be blocked from network access immediately. Use the vulnerability scanner to also check for activity on any wireless bands or channels you don’t usually use.

Read the 5 Steps here:

http://blogs.cisco.com/smallbusiness/5-steps-for-assessing-your-wireless-network-security/