Most Security solutions leverage a combination of signature and behavior based technology (more HERE). This worked in the past however today these solutions are not good enough regardless if you layer multiple products that are built upon similar scanning methods. There are many ways to bypass point Security products such as throttling behavior and masking the known fingerprint of the attack code. A example of a technique used to hide malware from popular Anti-Virus packages is leveraging Dynamic Obfuscation software.
Obfuscation software was designed to protect source code from piracy by making the original code more complicated to read while retaining functionality. There are commercial obfuscation software packages available for programmers looking to hide their source code which is also obtainable for malware developers. This is bad for anti-virus vendors responsible for developing methods to fingerprint malicious code.
Malware producers can make things even more difficult for Anti-Virus vendors by adding dynamic elements that randomizes malicious code and encryption keys on the fly. For example, a victim accessing a malicious website could see a different variation of the same exploit each session. Dynamic obfuscation provides an endless number of variants making it almost impossible for signature based Security to identify the threat.
There are dozens of examples for commercial Java obfuscator packages. Some common packages are Zelix KlassMaster, Dash-O, ProGuard, Smokescreen, Thicket and Allitori. Popular penetration toolsets such as Metasploit also include malware obfuscating modules such as the VoMM module. Research on VoMM from a few years ago can be found HERE .
Today’s Internet is a dangerous place. Imagine a small village with law and order surrounded by a wall keeping out miles of ungoverned ruthless territory. Most known websites surfed daily by your users make up a small percentage of the total Internet. The remaining 80% or more of uncategorized websites are contaminated with Botnets, malware and short-lived websites targeting your users. Many of these malicious websites are embedded in trusted sites such as social networks by hiding in advertisements or silly links posted by your friends. The best protection for this threat vector is limiting Internet usage to trusted websites and monitoring those websites for malicious applications.
The most common method to protect users while surfing the Internet is leveraging a web security solution. I wrote a post about this HERE. Cisco has two web security flavors, which are a dedicated proxy and application firewall add-on. The dedicated proxy, known as the Web Security Appliance (WSA) came from the acquisition of IronPort. Cisco replaced its content filter module for their ASA firewalls based on McAfee technology with an application aware addition known as CX Context-Aware. There are many overlapping features between the two approaches however there is a clear distinction when to choose one over the other.
Both CX and WSA provide features expected from a web security solution. Both CX and WSA offer the ability to monitor and control what type of websites are available for users based on categories (examples Adult, Hate, Gambling, etc.). Both CX and WSA include reputation controls meaning ability to blacklist known malicious websites (more on reputation HERE). Both CX and WSA can limit or deny traffic types based on user groups such as denying Skype, throttle download speeds and target specific applications (example permitting Facebook while denying Farmsville for employees 9am-5pm). Both solutions can scale beyond the internal network using VPNs to route traffic from remote users.
CX DASHBOARD (click to see larger)
CX Web Categories
IronPort WSA Categories
WSA Reputation Score Settings
Features offered by IronPort not included with CX are focused on what happens after traffic passes reputation and content policies. WSA offers anti-malware scanning licenses for McAfee, Sophos and Webroot for any traffic tagged as “grey” meaning traffic that passes the reputation blacklist but not considered completely trusted or “white-listed”. These signature-based verdict engines are licensed separately and can be stacked to provide a wide range of scanning capability. WSA also offers a dedicated layer 4 Botnet scanner targeting phone home communication from infected machines. These additional features provide more layers of defense beyond common application firewall technologies including Cisco CX.
Some other differences are based on the design and implantation of WSA and CX. The WSA is a dedicated proxy, which can be deployed using host inline proxy settings or directing network traffic to the WSA using WCCP. The CX uses policy maps routing traffic seen by an ASA through the CX addition. WSA includes caching to improve network performance. WSA can direct traffic through a DLP solution adding network based DLP scanning (A possible roadmap is including DLP in the appliance as a add-on license similar to the IronPort Email Security Appliance). Cisco roadmaps show IronPort offerings will include a virtualized option in the near future. Probably the most important CX design consideration is today Cisco ASA 5500X can either leverage CX or IPS however not both simultaneously. CX is also not available on some ASA 5500X models such as 5585-40s and 5585-60s. Expanding CX to other ASA models and dual IPS CX support are roadmap items at this time.
To summarize, its best to consider Cisco CX for essential web security meaning content filtering and reputation based protection. The CX is also a viable option if you don’t require IPS from your ASA 5500X. WSA is suited for Comprehensive web security meaning content filtering, reputation protection, malware scanning and layer 4 botnet awareness. WSA is also a dedicated proxy providing performance benefits as well as design options such as including Data Loss Prevention. If you desire your ASA to include IPS functionality, today you will need to consider a WSA to handle web security. Hopefully this post helps with distinguishing when to choose CX or IronPort WSA.
Here is a post from my friend Aamir Lakhani’s blog about RSA NetWitness. The original can be found at Cloud Centrics (http://www.cloudcentrics.com/). Really good post on NetWitness.
RSA NetWitness
RSA NetWitness is a unique solution that captures, store and analyze network data traffic. This gives you the able to see exactly what comes in and goes out of the network in real time . In simple terms, RSA offers to you a Network CCTV. Not only that, NetWitness also allows you to see the traffic in action as it reconstructs the data that flows through the network into its original format according to its own type or application. This helps you strengthen your security measures by taking appropriate action. On top of that, since all traffic is captured and stored, you will be able to go back to a particular period of time and conduct historical data analysis. Nothing escapes undetected.
RSA NetWitness delivers an innovative fusion of hundreds of log data sources with external threat intelligence to enterprises; enabling extraordinary broad and high-speed visibility into the critical information needed to help detect targeted, dynamic and stealthy attack techniques.
Why is it important?
NetWitness records all network activity. The benefits of this forensic analysis cannot be matched by any other product. NetWitness will truly allow you to investigate what happened on the network.
More importantly, since NetWitness sees and records everything on the network, it is very easy for the product to detect threats as they are occurring. This gives administrators an opportunity to stop attacks before they cause damage on the network.
Recording all network activity with forensic accuracy and analyzing current threats in real time provides situational awareness and insight for threats on existing infrastructure devices. Typically, when systems are discovered to be compromised, the systems are imaged, and software is reinstalled. However, many people don’t actually figure out the root cause of the problem. How did the system originally get compromised and what measures should be used to prevent it from happening again? In addition, if one machine is compromised, chances are high that others will be as well.
Why are these attacks difficult to detect? The answer is that these threats originate from the inside, or trusted areas of the network. The most common network threats involve a failure in internal security. This includes APTs, Botnets, Phishing attacks, social network information leakage, and product patches.
Security fails and systems get breached because many people do not take the threat seriously or make an effort to learn about it. It takes a proactive approach to be secure and protected against threats.
Furthermore, many organizations have processes in place that actually do more harm than good. These procedures that are supposed to help an organization’s security posture degrade it instead. This is partly to do with people and attitude, but also partly to do with outdated ways of thinking about security mixed with inadequate technologies.
Anatomy of an attack
Here is an example: Zeus was a popular attack last year that stole and spread through internal networks. Zeus is a Trojan horse that steals banking information by Man-in-the-browser, keystroke logging and Form Grabbing. Zeus spread mainly through drive-by downloads and phishing schemes.
Zeus was successful because it was a well-crafted phishing attack. Victims received an email that looked interesting to them. They were instructed to download a report from what appeared to be a legitimate website. In reality, the report was a Trojan horse that allowed attackers to control the victim’s system. The hosting website was in China.
A capture (report) from NetWitness showed that the originating server of Zeus went to a command and control server in China. The program that the user downloaded allowed attackers from the Chinese server to have control of the users’ system. From that point on, it was trivial for them to exploit other systems on the users’ network.
Most anti-virus agents did not detect Zeus. Later, Zeus disabled anti-virus agents using a variety of schemes – mostly by redireiting anti-virus updates to a 127.0.0.1 IP address.
Since NetWitness recorded all network traffic, it recorded what systems were compromised, communications with systems in China, and what was being transferring. When internal systems initiate a connection and transfer files, NetWitness captures that traffic.
NetWitness is the only security tool that provides complete visibility on a network. It shows when attacks are occurring in real-time and gives an organization the ability to detect and stop those attacks.
The web is a dangerous place so its extremely important to have web proxy / content filter technology protecting users that access it. I had a roommate years ago who purchased a computer and within hours had every virus, malware and what not clogging his new machine. I’m sure he didn’t have the best surfing habits however that doesn’t mean the average user is less likely to be infected. What most people don’t realize about websites is they are like a Paint By Numbers canvas leveraging other websites to fill in the colors. For example, if you see a RealAudio video on a website, guess what … you have surfed both that embedded video’s website and the host website. The same goes when there are hidden links that download malicious malware on what you believe is a safe website.
The standard defense for Internet based threats is a web proxy / content filter solution or similar features imbedded in a firewall, IDS/IPS or SAS offering. The baseline solutions offer Content Filtering meaning the ability to monitor or block web content that violates specified policy. The major players do this well (Bluecoat, Websense, McAfee, Iron Port, etc.) by grouping web content into categories. For example, an administrator can deny all adult websites by blocking the adult category, which is an up-to-date list of the known adult sites. Smaller players work like an access-list manually blacklisting websites, which is a nightmare to manage. In the end, this is a commodity feature for the real players and should come standard for web proxy / content filter solutions with little management to maintain content categories.
Besides denying policy, web security / content filter solutions should have a method to check web traffic for threats. Many vendors offer anti-virus, anti-malware and content scanners that look for malicious traffic inline by redirecting network traffic through a web security / content filter or by endpoint proxy settings forcing endpoint web traffic to the security solution. Some verify content for hidden attack vectors in a closed environment prior to permitting access to the website (also known as sand-boxing). The best web security / content filter solutions offer a mix of signature and behavior sources since no single source can cover the entire gamut of web attacks properly. It’s also important that the web proxy / content filter solution is capable of viewing https IE secure channels or you will miss end user traffic that is encrypted.
Reputation or website “credit scores” is becoming a popular factor utilized by web security / content filter solutions. My blog on this subject explains this HERE. Reputation is key for speeding up the security process since many harmful websites can be denied based on reputation rather than scanning and identifying threat signatures or malicious behavior. I’ve used solutions such as IronPort Web Security Appliance (WSA) and usually 90-95% of the websites denied are identified as malicious based on reputation rather than passing the reputation check and caught by other security defenses.
The final point about securing access to the Internet is to consider email and web as equal targets since they are the most common cyber attack vectors. Web proxy / content filters need the same investment as Email Security and must be designed as a unified solution. I’ve had customers say “we get phishing attacks that send clean emails with links to malicious websites”, which users clicking the links is a Web Security vulnerability … not email. Other investments should be made in post compromised technology such as botnet / malware detection technology (Netwitness, Wireshark, Ironprot WSA botnet scanner, FireEye sandbox technology, etc.), Data Loss Prevention and host based security. No solution is a silver bullet so a layered defense will dramatically reduce risk if the overall design compliments each solution rather than operates individually.
