Developing an Effective Strategy for Application Security

Web Application security is perhaps the most common and frequently discussed topic among researchers, small businesses as well as large enterprises. The primary reason is that, it has long overtaken network in being the most commonly attacked layer in a given IT infrastructure. Network and Operating System security has matured to a certain extent. Combined with various OS level hardening mechanism, the traditional attacks against network services has largely been mitigated or has become significantly costly. However, when it comes to web applications, for some reason, it appears that similar maturity in terms of risk mitigation is not achieved yet. Despite multiple WaF products and other security solutions for Web App security, the number of incidents related to compromise of organisation and its data by exploiting issues in web application has only increased in recent times.  For this reason, a different strategy or approach is required in order to safe guard web applications and implement a practice that encourage secure web application development.

Let Numbers Speak for Themselves

In order to better visualise the changing (or perhaps changed) Threat Perception in application and its associated infrastructure, let us consider the case of a Web Server and two web application development framework that is very popular among enterprise application developers - SpringSource Spring and Apache Struts. The statistics reveal that the number of vulnerabilities in the web server software itself is on a reducing path. The actual threat perception is significantly low compared to the numbers due to the existence of various OS level mitigation strategies that makes exploitation of memory corruption and other similar issues in web server process extremely costly/difficult. However, for web applications, the vulnerability classes are significantly different from those mitigated at OS level. New techniques and ease of exploitation has greatly increased the threat perception for web applications and web application development frameworks. Apart from common vulnerability classes, business logic vulnerabilities are another important issue that affects a lot of web applications.

Statistics for SpringSource Spring Framework

Statistics for Apache Struts Framework

Vulnerabilities in popular web application development frameworks are particularly critical due to the widespread impact. Since large enterprise applications are not easy to upgrade due to multiple dependency, vulnerabilities in framework software are extremely critical for such application and must be mitigated if not patched immediately.

Evaluating The Application Security Maturity

There is no single strategy that can help all organisations define a suitable approach for application security. There are various models, however, a carefully chosen model has to be customised and adopted based on the current posture, need and roadmap of any given organisation. Therefore, in order to define a suitable policy, it is very important to evaluate and ascertain the current application security maturity level of an organisation. This can be done to a certain extent by asking few questions:

1. Is application penetration test (or VA as widely called) conducted regularly on all important applications?
   
2. Are the same vulnerability classes for e.g. SQL Injection or CSRF detected every time a security test is conducted?
   
3. Is there a training and evaluation program for developers?
   
4. Is enforcement of secure coding guidelines implemented in IDE (or similar) level?

[1] The above questions helps in ascertaining the current security posture of an organisation as well as, to some extend, provides a direction for improvement in application security maturity. For example, if you have never done a Penetration Test on your applications, there is probably no need to immediately think of high level security policies or strategies, rather the organisation should focus on initiating regular security testing practices. [2] On the other hand, if you have been doing Penetration Testing for some time, however every time the same classes of vulnerabilities are discovered in different applications or newly implemented features, perhaps its time to think about the effectiveness of the strategy and its RoI. [3] & [4] are strategies that need to be adopted in order to avoid recurring vulnerabilities of similar classes.

Towards an Effective Strategy for Application Security Maturity

A good strategy for implementing or improving application security in an organisation should consists of at least the following:

• Regular security testing of all applications against commonly occurring and newly discovered vulnerabilities.
• Comprehensive security test covering maximum functionalities and business logic must be done for at least business critical applications if not all.
• Vulnerability intelligence - Identify which classes of vulnerabilities has been detected the most in applications. Also identify if similar classes of vulnerabilities are introduced in newly developed applications and/or features.
• Developer training on how to fix, avoid and mitigate security vulnerabilities is a must. This helps in ensuring that similar vulnerabilities are not re-introduced in future development efforts.

In general, the security strategy for most organisation is reactive in nature i.e. we react to discovered vulnerabilities by patching or mitigating the threat via. workarounds. For organisation with greater threat perception, this cannot continue for ever! An organisation must develop a security roadmap that consists of moving forward - Reactive to Proactive and finally towards Predictive.

For almost a decade, implementing security in an organisation usually started with a VA or PT, followed by patching of discovered issues. However, due to the nature of current threats and skill level of adversaries, it is not enough to continue fixing issues discovered during VA/PT. This method just don't scale and becomes almost unmanageable for large organisations with wide range of assets. It is important for an organisation to be more proactive where it mitigates common classes of vulnerabilities and work towards a better security development life-cycle where common security issues are avoided at design and development stage only.

Some of the points that should be considered while developing an application security strategy:

• Regular security testing
• Vulnerability management & intelligence
• Security as a part of Development/SDLC
• Developer training and skill development
• Operational Security (secure deployment and management of apps)

Attack Patterns of 2013 and Lessons for the Future

Verizon DBIR 2014 is one of the most comprehensive and well researched report on various attacks and data breaches as seen by companies involved in attack & incident analysis and threat intelligence during 2013.

2013 Attack Patterns

As per the Data Breach Investigation Report (DBIR), year 2013 has seen top attacks and incidents in the following areas:

• Point-of-Sale Systems
• Web Applications
• Cyber Espionage
• Attack on Financial Services

Top attack patterns

Point of Sale (POS) Systems

It was found that majority of the attacks on POS systems were external in nature i.e. from outside the operating network. The intruders used simplistic scanning tools for identifying POS systems over the Internet. Once identified, guessed (educated) passwords and public exploits were the main tools of compromise to gain access in the systems. RAM scrapers were the primary tool of choice for these threat actors to collect decrypted payment related information including credit card details.

Web Applications

Web applications are surely the target of choice for most attackers. The amount of bug bounty earned by researchers across the world from companies like Google, Facebook, Paypal etc. for web application vulnerabilities speak for it.

• Facebook pays researcher $33,500 USD for reporting security vulnerability
• Facebook pays research $20,000 USD for reporting security vulnerability
• Paypal pays research $3000 USD

However it must be considered that Bug Bounty programs should not be treated as a replacement for conventional Penetration Testing. The two approaches are complementary to each other. Any professional services engagement is usually time boxed and ideally should focus on core aspects of the security of target applications including its possible attack surfaces and issues that directly affect the business operations of the application. Given a large application, it may not be possible to identify all possible vulnerabilities within the defined time frame. This is where the Bug Bounty model comes in. The crowd sourced nature and pay per vulnerability model is effective in identifying and eliminating maximum low hanging fruits in the most cost effective manner. This is a typical case of - Given enough eyeballs, all bugs are shallow. It should also be noted that really complex and interesting vulnerabilities in popular services such as Facebook, Google, Github etc. has also been disclosed as a part of Bug Bounty initiatives. However due to the sheer volume of web applications, it is generally a better approach to consider both professional Penetration Testing and Bug Bounty programs for an effective security testing strategy.

Insider Abuse

It is relatively well known that an Information Technology infrastructure faces threat not only from outside its corporate network but also from inside. There has been multiple cases where Threat Actors were found to be insiders or assisted by insiders.

However it should be considered, due to lack of security awareness and operational security practices, insiders may end up being the pawns or pivot for launching attacks from inside the local network. The exploits of Syrian Electronic Army has highlighted the need for appropriate operational security practices. Even the strongest and most secure IT infrastructure may end up compromised due to lack of security awareness of those operating the systems. Hence it is very important to consider security in all three aspects viz. People, Process & Technology.

Shifting Motivation for Threat Actors

The DBIR also highlight an interesting pattern - The shifting motivation of Threat Actors. This is something inevitable given the rise of Bug Bounty programs and determination of important software vendors to consider defence-in-depth through exploit mitigation techniques to seriously increase the cost of practical attacks.

Threat actor motivation over time

Unlike popular perception, it turns out that random hacking incidents are relatively rare and most of the incidents so far are clearly motivated by economic gains. However over time, the data shows that the threat actors are shifting from Financial fraud to espionage related activities. This is probably an indicator of the growing importance of cyber medium for security agencies of various governments. This might also be an indicator of the growing cost of conducting practical attacks using sophisticated tools and 0day exploits.

Lessons or Inferences from the Investigation Report

• POS System compromise could have been prevented by minimum security investments - Penetration Testing and basic Operational Security like strong passwords, use of Anti Virus etc. could have prevented a majority of the incidents.
  
• Web Application vulnerabilities are still prevalent. The industry in general is very much aware of the issues and the rise of bug bounty programs might help curb misused vulnerabilities to a certain extend as long as companies do not replace conventional Penetration Testing with Bug Bounty programs - they complement each other.
• Espionage "industry" is on the rise. The amount of leakage from relevant agencies involved in Cyber Espionage and exposure from their contractor companies provide enough evidence of its rise and prevalence. Growing investment will encourage researchers to continue innovative security research. Highly sophisticated tools and exploits will continue, but cost of entry will be very high.

General Takeaway

• Minimum security investment is a must for any IT based business.
• For organisations with serious security concerns - It is very important to realise that security cannot be achieved by a one-time investment. It is a practice that involves regular activities and development of individuals responsible for its operations.
• Human Factor is an important aspect of the overall organisational IT infrastructure. Security development/maturity of the human factor must be equally considered along with the Technological aspect.
• Vulnerabilities will exist. Most leaders in this business accept this fact and is working towards Defense-in-Depth. However you must reach a certain security maturity level in terms of your internal practices and externally exposed risks before you can start considering such strategies effectively.