Security Considerations in Custom Software Development

Bidhan Baruah

October 13, 2023

Better security can be an advantage of custom software development over commercial solutions—but only if you take the proper precautions during development. 

Criminals target commercial software because there’s usually a bigger payoff. Once they find a successful exploit, they can use it against every business that purchased the breached software to gain access to massive amounts of data.

When thieves attack custom software, often it’s because they’re specifically targeting the company. They often can’t use known exploits, so they have to start from scratch. This combination of greater effort and limited reusability often dissuades them.

Therefore, with strong cybersecurity measures and the advantage of being custom-built, you stand a better chance against attacks.

This article offers insights and effective strategies for security considerations.

Common Software Vulnerabilities

Injection Flaws

Injection flaws remain a prevalent threat to software security. These vulnerabilities arise when untrusted data is mistakenly sent to an interpreter as part of a command.

A typical example is SQL injection, which pertains to the malicious insertion of SQL code into a query.

The consequences of such exploitations can be severe. An attacker can gain unauthorized access to data and corrupt, delete, or, in extreme cases, take over a system completely.

Mitigating these vulnerabilities involves using parameterized queries, strict whitelisting, and avoiding dynamic queries.

Cross-site Scripting (XSS)

Cross-site scripting, commonly abbreviated as XSS, is a vulnerability that occurs when a software application includes unvalidated or unsanitized user data on a web page.

This allows attackers to execute malicious scripts in an unsuspecting user’s browser. Such scripts can lead to various adverse outcomes, including stealing user data, defacing web pages, or even distributing malware.

Combatting XSS requires a multi-pronged approach: one should validate and sanitize all user inputs, employ Content Security Policies (CSP), and lean on security libraries and frameworks designed to counter these flaws.

Cross-site Request Forgery (CSRF)

CSRF is a technique attackers use to trick victims into making unintended requests to web applications where they’re authenticated, effectively leveraging the user’s identity and privileges without their knowledge.

The consequences can be profound, leading to unwanted actions performed on behalf of the victim, from data changes to unauthorized operations.

Defenses against CSRF include the utilization of anti-CSRF tokens and ensuring that state-changing operations are backed by authenticated requests. Implementing the “same-site” cookie attribute can strengthen defenses against this threat.

Insecure Direct Object References (IDOR)

IDOR vulnerabilities emerge when attackers can directly access or manipulate objects, such as files or database entries, by tweaking input parameters.

This kind of exploit can facilitate unauthorized data retrieval, tampering, or even outright deletion.

To guard against IDOR, it’s crucial to validate user inputs against a whitelist of allowed values, institute robust access control mechanisms, and ensure that direct object references, like specific database keys, remain hidden from end-users.

Security Misconfigurations

An all-encompassing term, “Security Misconfigurations” refers to various potential oversights where the software or its associated systems are improperly configured, resulting in vulnerabilities.

Such misconfigurations can lead to unguarded system data access, total system breaches, or even the dumping of entire databases.

To defend against this, organizations should regularly audit both application and server configurations, prune unused features and accounts, and ascertain that error messages remain opaque, not giving away critical information.

Emerging Threats and Trends

Ransomware Attacks on Applications

In essence, ransomware is malware that encrypts a user’s data and holds it hostage until a ransom is paid to the attacker.

For businesses, this can cause operations to grind to a halt, result in the financial loss of paying high ransoms, and potentially result in irreversible data loss.

The most effective shields against ransomware include maintaining up-to-date backups of critical data, regularly updating systems and software, and investing in trustworthy security solutions.

Moreover, training employees to recognize and avoid phishing attempts is essential, as these are common ransomware delivery methods.

API Security Concerns

Application Programming Interfaces (APIs) have become essential for interconnectivity. However, they are also increasingly becoming targets for attackers, mainly when inadequately secured.

Vulnerable APIs can be a gateway to data breaches, denial-of-service attacks, or even the exploitation of interlinked systems.

Safeguarding APIs demands various measures, including implementing rate limiting, rigorous input validation, and robust authentication mechanisms.

Moreover, regular audits and penetration testing focused on APIs can identify and rectify potential weaknesses.

Cloud-native Application Vulnerabilities

The shift towards cloud-native applications, specifically designed to thrive in cloud environments, has brought unique security challenges.

Misconfigurations or lapses in cloud-specific security practices can make these applications susceptible to unauthorized data access, breaches, or service disruptions.

To securely operate in the cloud, it’s imperative to grasp the shared responsibility model laid out by cloud service providers. Organizations must also establish robust Identity and Access Management (IAM) policies and continuously monitor their cloud environments for anomalies.

IoT (Internet of Things) Security Challenges

The Internet of Things (IoT) expansion has connected an ever-growing number of devices to the Internet. Many IoT devices lack security features, making them vulnerable to exploitation.

Successful attacks can lead to unauthorized device control, data theft, or even using the compromised device as a springboard to infiltrate broader networks.

Defending against IoT threats requires a shift in approach: default credentials on devices should be promptly changed, device firmware needs regular updates, and network segmentation strategies should be employed to isolate IoT devices from critical organizational systems.

Secure Design Principles

Least Privilege Principle

At the heart of secure software design lies the principle of least privilege.

This principle dictates that any software component, system, or process should only have access to the information and resources that are essential for its legitimate purpose.

By limiting permissions and capabilities, the potential damage from breaches or system failures is substantially minimized. It’s like giving employees only keys to the rooms they require for their job.

Defense in Depth

Defense in depth is the cybersecurity equivalent of multiple layers of security.

It operates on the premise that no single security measure is infallible. By implementing multiple layers of defense strategies, even if one layer gets compromised, others remain to block an attacker’s progress.

Think of it as a castle with multiple walls, moats, and guards, each serving as a separate line of defense against potential invaders.

Fail Securely

Software and systems inevitably encounter errors. However, how they respond to these errors can make a difference between a minor hiccup and a major security incident.

The principle of “fail securely” emphasizes that systems should handle errors in a manner that does not leave them vulnerable. For example, if an authentication system fails, it should deny access by default rather than granting it.

Economy of Mechanism

Simplicity is the cornerstone of the economy of mechanism. The principle advocates for keeping security designs as simple and small as possible.

Complex systems are harder to understand, analyze, and secure.

Keeping the mechanisms simple makes potential flaws easier to spot, and the system becomes more maintainable and secure in the long run.

Open Design and Security Through Obscurity

Open design operates on the belief that the security of a system should not depend on the secrecy of its design or components. Transparency fosters trust and allows for community vetting, often revealing vulnerabilities that can be addressed.

This contrasts with “security through obscurity,” which relies on secrecy as a primary defense. While obscurity can be an additional layer, it should never be the sole protective measure.

Secure Coding Practices

Input Validation and Output Encoding

One of the fundamental rules in secure coding is never to trust user input. All inputs should be rigorously validated for potential malicious content, ensuring they meet the expected format and length.

On the flip side, output encoding ensures that any data displayed to the end user does not execute maliciously.

These practices effectively mitigate common vulnerabilities such as injection attacks and cross-site scripting.

Secure Error Handling

Errors are inevitable in any system. However, revealing too much information in error messages can give attackers insights into the system’s inner workings.

Secure error handling involves displaying generic error messages to users while logging detailed errors internally for diagnostics. This balance maintains usability while protecting system details.

Secure Data Storage and Transmission

Protecting data, both at rest and in transit, is paramount.

Data storage should incorporate encryption techniques to safeguard sensitive information.

Simultaneously, data transmission should utilize secure protocols like HTTPS to ensure data integrity and confidentiality during transit. Regularly updating cryptographic methods and keys further enhances this protection.

Principle of Least Exposure

Similar to the least privilege principle, the principle of least exposure focuses on minimizing the exposure of application components to other parts of the software and the outside world.

Potential attack vectors are reduced by ensuring that only necessary components are exposed.

Security Testing Tools

Static Application Security Testing (SAST)

SAST tools, also known as “white-box testing” tools, are instrumental in evaluating source code, bytecode, or binary code of applications without executing them.

They scan codebases for patterns or configurations that hint at potential vulnerabilities, enabling developers to identify and rectify security issues during the coding phase.

By pinpointing vulnerabilities early in the development process, teams can mitigate risks before they escalate, ensuring a more secure and robust final product.

Dynamic Application Security Testing (DAST)

DAST tools operate on the opposite end of the spectrum from SAST, functioning as “black-box testing” tools.

They assess applications in their running state, identifying vulnerabilities that manifest during operation.

By simulating real-world attack scenarios, DAST tools highlight potential threats that an attacker could exploit, providing invaluable insights into a system’s real-time security posture and enabling timely remediation.

Interactive Application Security Testing (IAST)

Blending the strengths of both SAST and DAST, IAST tools evaluate applications in their running state while also having knowledge of the underlying code.

This hybrid approach offers deeper insights into the application’s security profile. IAST tools can precisely pinpoint vulnerabilities and their locations in the codebase, accelerating the remediation process and enhancing application security.

RASP (Runtime Application Self-Protection)

RASP technology embeds protection measures directly within the application.

It operates in real-time, continuously monitoring the application’s behavior and responding instantaneously to threats.

Should any malicious activity be detected, RASP can halt the action, alert the necessary parties, and even adapt the application’s behavior to bolster defenses. This proactive approach ensures threats are neutralized at their inception, safeguarding the application and its data.

Secure Development Environments

Sandboxing and Virtualization

Sandboxing provides a secure, isolated environment for running untested or untrusted programs. By confining these programs to a controlled space, any potential malicious behavior is contained, preventing it from harming the broader system.

Virtualization, on the other hand, involves creating virtual instances of systems or applications, ensuring that any potential threats don’t compromise the primary system.

Sandboxing and virtualization ensure that testing and development occur in secure confines, away from critical systems.

Container Security (e.g., Docker, Kubernetes)

Containers, popularized by platforms like Docker and orchestrated by systems like Kubernetes, have revolutionized software deployment.

These lightweight, standalone packages contain everything required to run a piece of software. However, they also introduce unique security challenges. Ensuring container security involves practices like scanning container images for vulnerabilities, employing runtime security measures, and ensuring proper configuration of container orchestration tools.

With secure containers, developers can enjoy the flexibility and scalability of containerized applications without compromising security.

Secure CI/CD Pipelines

Continuous Integration and Continuous Deployment (CI/CD) pipelines facilitate rapid development and deployment of software. However, ensuring these pipelines are secure is paramount.

Secure CI/CD involves integrating security checks at every stage, from code integration to deployment. Automated security scans, vulnerability assessments, and environment hardening are all part of a secure CI/CD process, ensuring that as software evolves and deploys, it remains robustly defended against threats.

Lay a Strong Foundation

Merely reacting to threats as they arise is similar to playing a never-ending game of catch-up—a strategy that is both exhausting and ineffective.

By embedding strong security measures throughout the software development lifecycle, you harden your software against even the most sophisticated threats. It’s not just about building walls but ensuring the foundation is strong.

With diligence, foresight, and a commitment to excellence, you can ensure the security of your custom software and the sensitive data it contains.