Applications are a key component of virtually any IT environment. For that reason, managing application security is one of the most important pillars of any cybersecurity strategy. Unfortunately, application security is also challenging - many different types of threats can impact applications, and there are many steps that organizations must take to mitigate them.

With that reality in mind, this article breaks down everything you need to know about application security -- including what it means, why it's important, best practices for securing applications, and emerging application security trends.

What is application security?

Application security (AppSec) refers to the tools and practices that organizations use to defend software applications against attack. It addresses every type of threat that can affect applications – from authentication and authorization risks to insecure data management, code injection vulnerabilities, and beyond.

Application security is distinct from other categories of cybersecurity, such as network security (meaning the practice of mitigating threats at the network level) and cloud security (which focuses on securing cloud infrastructure and services). That said, there is a close relationship between application security and other types of security. For instance, since many application vulnerabilities can be exploited remotely over the network, securing the network also helps to secure applications.

The importance of application security

Applications are the centerpiece of most IT environments, making them one of the most alluring targets for attackers.

If threat actors launch successful attacks against an application, they may be able to exfiltrate sensitive data that the application can access. They could also potentially perform harmful actions, such as deleting data or sending malicious messages to users. In some cases, they could even take control of the server that hosts the application, and then use it as a springboard for launching other attacks.

By mitigating the various techniques that attackers can use to compromise applications, application security helps prevent such risks.

Application security risks

The specific types of application security risks and threats that an organization needs to manage can vary depending on which type of applications it deploys. For example, if you only use stateless applications (meaning applications that don't store data persistently), you don't need to manage the encryption of data at rest because your applications simply would not store data at rest.

In general, however, application security covers the following risks:

• Authentication and authorization: Authentication and authorization are the processes that applications use to validate users. Application security strategies must ensure that users without the proper permissions cannot access application capabilities that should not be available to them.
• Access controls: Access controls govern which resources applications can access and integrate with. Oversights in access control settings could expose applications to attack or cause them to "leak" sensitive data.
• Logging: While logs themselves don't typically lead to direct attacks against applications, logging is an important component of application security because teams often rely on log data to identify and investigate threats. Thus, developers must make sure that applications log information relevant for security purposes, such as authentication events.
• Vulnerability management: An application vulnerability is any type of flaw that attackers can exploit to access data or features that should not be available to them. Scanning applications for known vulnerabilities is critical for preventing attacks.
• Code injection: Code injection is a type of attack wherein threat actors manipulate application input to run malicious commands. Code injection risks can result from known vulnerabilities that are recorded in public vulnerability databases, but they can also stem from flaws unique to an organization's internal source code. Either way, finding and remediating application code that enables injection attacks is critical for securing applications.
• Patching: Software patching ensures that applications are up-to-date. This is important because patches often provide security updates that fix known vulnerabilities.
• Threats: A threat is any type of attack that threat actors could potentially carry out. Tracking threats, which teams can do via a process known as threat intelligence, is important for identifying emerging attack techniques or new types of application vulnerabilities.

The challenges of modern application security

The main challenge of application security is that there are many ways for attackers to compromise apps. As a result, there is no single set of processes or tools that teams can use to secure applications.

Instead, application security requires a complex, multi-pronged approach that addresses the wide variety of threats and risks described above. Organizations must be able to detect and remediate authentication risks, insecure access configurations, code vulnerabilities, and other types of liabilities. They must also ensure that their applications generate sufficient log data to enable effective security operations, and that they comprehensively patch applications. Furthermore, they must stay on top of emerging threats and attack techniques so that they can take measures to block them.

In addition, application security is a process that teams must integrate into multiple stages of the software delivery lifecycle (SDLC). They should consider application security when planning and designing a new application or application update to ensure that the application's architecture reflects security best practices (such as isolating sensitive data in order to reduce the risk of attack). They should scan application source code for security risks, then run additional tests after they have compiled applications. They should also perform ongoing security monitoring once an application is in production to detect attacks against the app.

Integrating security into the SDLC, and checking for risks at multiple stages, is important because different types of tests can reveal different application security problems. For example, some code injection vulnerabilities can be detected by running source code scans that examine how an application validates input and attempt to identify instances where input is not properly validated. But because there is no guarantee that source code scans will catch all injection vulnerabilities, it's also wise to run injection tests against live applications inside a testing environment to evaluate how they respond to malicious input.

By checking for the same types of application security risks using multiple techniques at different stages of the SDLC, teams maximize their chances of identifying problems before applications are deployed into production – at which time attackers can actively exploit any vulnerabilities.

Types of application security testing

Here's a comprehensive list of the main types of tests that can detect application security risks:

• Static Application Security Testing (SAST): SAST is the practice of scanning application source code or binaries in a non-running state. SAST focuses on identifying problems like known vulnerabilities, coding flaws, and insecure configurations in application packages.
• Dynamic Application Security Testing (DAST): DAST automatically checks for application security risks by simulating malicious interactions with running applications inside a test environment. The goal of DAST is to uncover problems that are not evident by scanning source code or binaries – such as, again, injection risks that source code scanners did not detect.
• Penetration testing: Penetration testing is similar to DAST in that it focuses on finding vulnerabilities by interacting with live applications in a test environment. However, penetration tests are typically done manually, whereas DAST is automated.
• Software Composition Analysis (SCA): SCA checks the dependencies and other third-party components of an application to detect risky code. It focuses in particular on identifying any insecure open source code that developers incorporated into an application. SCA can also help to identify potential open source licensing violations.
• API security testing: API security tests check for security risks in the API requests and responses that applications use. For example, API security tests can identify whether an API response contains sensitive data that is unencrypted. API security is arguably not a part of application security because APIs are distinct from applications; nonetheless, since many modern applications rely extensively on APIs to communicate with each other (and sometimes for internal communication as well), testing for API security risks is important for shoring up application security.

Application security trends in 2024

New trends surrounding how organizations build and/or use applications, as well as the growing popularity of certain types of attack techniques, are driving specific application security trends that organizations should follow if they want to stay at the forefront of application security.

Here's a look at key AppSec trends to watch in 2024.

API attacks

API attacks are not new, but they have surged in frequency in recent years and are poised to remain one of the most popular techniques that threat actors use to target applications.

As we mentioned above, API security is a bit different from application security because APIs and applications are not the same thing. However, because applications frequently depend on APIs to share resources and data, threat actors who compromise an API can often use the attack to breach applications as well.

This means that securing APIs is especially important as a complement to application security in 2024.

Supply chain security

Several of the most significant application security risks of recent years, such as the SolarWinds attack that was disclosed in late 2020 and the Log4j vulnerability discovered in 2021, have focused not on breaching applications used by just one company, but on compromising software that is used by a large number of organizations. This type of attack is called a supply chain attack.

From a threat actor's perspective, supply chain attacks are lucrative because compromising a single piece of software that forms part of many organizations' software supply chain gives attackers a back door into all of those organizations' IT environments. That's much more efficient than breaching just one company's app.

Like API attacks, supply chain attacks are not new, but they are surging in popularity. This makes supply chain security an especially critical part of application security.

SaaS security

Today, many organizations rely in part on software that is delivered to them via a Software-as-a-Service (SaaS) model. This means that they do not develop, deploy, or host the applications themselves. They rely on a third-party vendor to handle those responsibilities.

The fact that SaaS apps are developed and managed by an external vendor means that many of the core requirements for application security fall to the vendor. For instance, most businesses that use SaaS apps have no access to the apps' source code, so they cannot scan it for vulnerabilities.

Nonetheless, there are still some application security responsibilities that businesses must manage for themselves even when using SaaS. For example, they should ensure that access controls for their SaaS apps are properly configured to prevent unauthorized access or the leaking of sensitive data. They should also have transparency into any vulnerabilities that impact their SaaS apps. Even if you can't remediate a SaaS vulnerability yourself, you'll want to know when one exists and whether the vendor has patched it.

SaaS security is a complex topic, and a full discussion of it is beyond the scope of this article. But suffice it to say that as SaaS continues to be a dominant approach for running software, managing SaaS security challenges will be an increasingly important component of application security.

Application security best practices

When it comes to both traditional application security threats and more novel attack techniques, there are several best practices that teams should follow to minimize their risk of breaches that target applications:

• Run security tests across the SDLC: As we noted above, security tests at different stages of the SDLC can surface different security problems. To maximize your ability to detect application risks, test at all relevant stages of the SDLC. Testing only during the development stage or only right before deployment, for instance, may not be enough to find all flaws.
• Prioritize risks: Not all application security risks can cause the same level of harm. Some might be more challenging to exploit than others, for example, and some might cause severe disruptions while others are less serious. For that reason, it's a best practice to assess the severity of each application security issue you discover and prioritize it accordingly, being sure to fix the most serious risks first.
• Strive to shift left: While monitoring applications in production environments can help identify attacks, it's much better to find and remediate risks before applications ever enter production environments. Thus, while you should perform security monitoring to catch any risks that slipped past earlier scans, your main goal in application security should be to "shift left" by detecting problems as early in the SDLC as possible.
• Plan ahead for security remediations: It's one thing to discover a vulnerability or other risk. It's another to remediate it quickly. To ensure rapid mitigation, businesses should build a mature AppSec program that includes governance for vulnerability remediation.

How Checkmark helps with application security

Checkmarx's core mission is to help teams identify and fix application security issues early and often. By delivering a comprehensive set of application security testing capabilities – including SAST, DAST, SCA, API testing, and more – Checkmarx empowers teams to discover application security flaws at every stage of the SDLC. What's more, by providing actionable remediation guidance and vulnerability severity ratings, Checkmarx makes it easy to find risks and remediate them quickly and efficiently.
See for yourself by requesting a demo.