Application security testing (AST)

What is application security testing?

Application security testing (AST) — The testing, review, and analysis of the security integrity of applications as they progress through the software development lifecycle (SDLC).

Objective: Decrease the amount of vulnerabilities in applications, manage the potential consequences of active vulnerabilities being unaddressed, investigate and locate the causes of vulnerabilities in order to protect against future issues, and understand your organization’s application security posture.

Why is AST important?

Applications rely on open source code and are connected throughout various networks and clouds. This complexity leads to loss of visibility and greater security risk. By scanning applications and networks for vulnerabilities, weaknesses, and user verification, stability and integrity are increased.

Common features for AST

Several application security features assist developers in limiting vulnerabilities, protecting data, and allowing only authorized users to access their applications.

Authentication: Verifies that users accurately identify themselves. This can be done by requiring a username and password when logging in and enforcing multifactor authentication, so that users must verify their identity through one other device.

Authorization: Validates that users can access and use applications by matching the user’s credentials to an authorized user list.

Encryption: By encrypting sensitive data and traffic across public clouds, teams can hide important information from malicious actors.

Logging: Keeps track of who accessed sensitive information and how and when they did so to assist in investigations following security incidents.

Vulnerability detection: Monitors applications for common weaknesses, allowing teams to improve their integrity and security posture.

Application security testing: Uses a combination of these features when assessing the security of applications.

AST workflow

AST is commonly integrated throughout the SDLC to confirm that new or updated applications do not contain vulnerabilities. Security audits confirm that applications follow consistent and comprehensive security measures and that authorized users can access them. Then, penetration testers try to compromise applications to discover weaknesses. Finally, security scanning assesses the composition and health of applications.

The scope of AST

AST typically applies to three different types of applications: web, mobile, and cloud.

Web applications: These applications are used across the Internet, where information is shared across remote servers. Firewalls, which inspect and block harmful data packets, are traditionally used to protect organizations' networks from intrusions.

Mobile applications: These apps distribute and receive information from the Internet rather than from private networks, making them susceptible to attack. Virtual private networks (VPNs) are commonly used to protect applications on public networks, and IT teams may scan applications to verify that they follow security policies before they are used on mobile devices that are connected to their company’s network.

Cloud applications: These share resources and interact with other dependencies, requiring detailed scanning and visibility of their composition, vulnerabilities, and how they communicate with other components to calculate their integrity and blast radius and protect sensitive information.

Common attacks that target applications

Software supply chain attacks, code injections, and permission escalations are common attack methods that jeopardize the health of applications and victims’ systems.

Software supply chain attacks: Malicious code is embedded into open-source packages or software updates, and when end users integrate these resources into their systems, the systems become compromised.

Code injection: Malicious actors insert malicious code into applications to exploit victims’ environments. SQL injections are the most common, with attackers inserting SQL statements into applications to see or modify sensitive information.

Permission escalation: Attackers exploit poor permissions controls to slowly gain greater access to codebases to steal, exploit, or remove privileged information.

Popular AST tool categories

SAST: Static application security testing tests source code that is developed internally, finds vulnerabilities and where they are located in pre-production, and enforces white-box security testing.

DAST: Dynamic application security testing tests applications that are running, finds misconfigurations and vulnerabilities in production, and enforces black-box security testing.

SCA: Software composition analysis identifies risks and vulnerabilities for open-source packages, provides built-in policies and compliance auditing, and generates software bills of material (SBOMs) to discover components’ composition.