Simple and Stronger Mobile App Security with Automatic RASP Injection

According to recent research from Enterprise Strategy Group, 93% of organizations believe their mobile security protections are adequate. Yet those same organizations reported an average of nine mobile app security incidents in the past year alone. The consequences shared by survey responders include financial loss, legal exposure, downtime, fraud, and lasting damage to brand trust.

Building and maintaining strong, multi-layered mobile app defenses manually is challenging, time-consuming, and prone to errors. Development teams already face tight deadlines and complex regulatory demands. Adding dozens or even thousands of runtime checks across a large codebase is simply not realistic without automation.

For too long, the complexity of implementing runtime protections has been a barrier to adoption. Let’s change that scenario for you in this blog.

By automatically distributing and randomizing checks across application code and dependencies, developers and security teams raise their protection baseline without slowing down mobile app development.

What is RASP, and why is it important?

Runtime Application Self-Protection (RASP) is a set of defensive techniques embedded directly into a mobile app to detect and respond to attacks as they happen. Unlike static protections such as obfuscation or encryption, RASP focuses on runtime threats when the app is running on an end-user device.

For mobile apps, runtime threats include:

• Repackaging attacks: Attackers modify and redistribute your app to capture sensitive data such as passwords, credit card numbers, or health records.
• Key extraction: Even if secrets are obfuscated, they must eventually be decrypted in memory. Attackers can hook into the running process to extract encryption keys, enabling fraud or impersonation.
• Traffic redirection: By tampering with app libraries or device settings, attackers can redirect users to malicious sites or inject fraudulent payment flows.
• Bypassed license checks: Attackers can disable or bypass license validation, enabling piracy, cheating in games, or cloning premium features.

RASP mitigates these risks by embedding active defenses into the app, such as debugger detection, hook prevention, tamper checks, and certificate verification. These checks make it far more difficult for attackers to observe, alter, or exploit an app at runtime.

Why automated RASP is a better RASP

Historically, RASP checks were distributed via Software Development Kits (SDKs), requiring developers to manually insert function calls into their code. While this gives fine-grained control, it introduces two major challenges:

• Maintenance Overhead: Implementing and updating dozens or thousands of checks requires developer effort and discipline. Centralizing them into one place makes them easier to maintain, but also creates a single point of failure that attackers can target.
• Predictability: Once an attacker identifies where checks are placed in one app version, they can easily locate them again in the next build, even if the code is obfuscated. This predictability erodes long-term resilience.

Automated RASP injection solves both issues

Automated RASP checks are configured, not coded. Developers specify where to apply protections, and checks are automatically injected during the build process. Checks are distributed across different parts of the application, including dependencies without source code, and their locations vary across builds. This polymorphic behavior invalidates attackers’ prior analyses, forcing them to start from scratch with every release.

In real-world apps, automated RASP can help inject tens of thousands of checks far more than a development team could manually manage—creating a dense, moving target for attackers.

Practical tips on where to inject RASP checks

When designing your RASP strategy, you must strike a balance between security coverage and performance impact.

1. Cover security-sensitive code

Always include classes handling sensitive operations, such as authentication, encryption, payment processing, or license validation. Injecting checks in these areas ensures that even if attackers find ways to bypass some defenses, critical functions remain guarded.

2. Expand coverage for resilience

Beyond sensitive areas, the wider the coverage, the harder it is for attackers to disable all checks. Automated injection makes it feasible to distribute checks broadly without manually writing code.

3. Exclude performance-critical code

Some checks add minimal overhead, but in performance-sensitive areas, such as real-time graphics or networking loops, you may want to exclude injection. Guardsquare filters let you tailor coverage while consulting performance tables to guide tradeoffs.

4. Exclude trusted third-party libraries

For example, security SDKs that already contain their own integrity checks should not be targeted.

With Guardsquare, configuration filters let you fine-tune these rules. By default, the tool applies the widest possible filter, but teams can customize it to optimize for their app’s unique performance and dependency landscape.

Types of RASP checks and responses

Guardsquare supports a comprehensive set of RASP checks to counter the most common runtime threats. Examples include:

• Debugger detection: Identifies when a debugger is attached, a clear sign of reverse engineering.
• Hook detection: Blocks dynamic instrumentation tools that attempt to alter app logic.
• App tamper detection: Detects library or binary modifications to prevent malicious changes.
• Certificate and application integrity: Protects against resigning and unauthorized redistribution.
• System library integrity: Ensures underlying system libraries are not tampered with.

These checks can be configured with different injection policies:

• Entry-point checks: Run before the user can interact with the app.
• Spray checks: Randomly distributed across all eligible code for broad coverage.
• Checkpoint checks: Triggered before specific functions (e.g., PIN decryption) to protect critical workflows.

Each check can trigger a configurable response, such as:

• Blocking or terminating the app.
• Returning false data to mislead attackers.
• Calling a custom callback function to trigger alerts or adapt behavior.

Callback functions are compiled into the app binary and protected by multi-layered obfuscation. Teams can define their own handlers (e.g., jailbreak_callback) and configure them.

Monitoring and alerting in real time

Detection is only part of the equation, security teams also need visibility. Guardsquare’s threat monitoring platform, ThreatCast, provides real-time reporting of threats detected in the wild.

Key features include:

• Monitoring scope: Threats detected during app launch and throughout runtime.
• Frequency: Real-time reporting, triggered only when threats are observed, minimizing performance impact.
• Context: Rich data such as timestamp, device brand/type, geo-location, deviceID, and evidence of the attack.
• Notifications: Configurable alerts and webhooks to integrate with on-prem SIEM or monitoring tools.

Benefits of automated RASP injection

Automating RASP injection delivers multiple benefits over manual or SDK-based approaches:

• Improved security: Randomized placement across builds invalidates previous attacker analyses.
• Enhanced resilience: Tens of thousands of checks across code and dependencies increase attacker workload.
• Flexible strategies: Choose from entry-point, spray, or checkpoint injection policies.
• Simplified maintenance: No manual coding required—reduce human error and save development time.
• Continuous updates: Automatically benefit from Guardsquare’s latest optimizations and security enhancements.

Designing a RASP strategy to obtain the best resilience without compromise

A successful RASP strategy balances resilience, performance, size, and configurability. Guardsquare’s approach focuses on:

• Resilience: Checks are polymorphic across builds, diversified in location, and obfuscated to resist static and dynamic analysis. No “fingerprint” of Guardsquare is present in the app.
• Startup performance: Conforms to OS best practices. Performance impact is predictable and visible to developers.
• Runtime performance: Optimized for minimal UX impact, no crashes, delays, or Apps Not Responding (ANRs).
• Size: Impact is predictable and manageable, important for SDK publishers.
• Configurability: Minimal complexity; only essential knobs exposed to developers.

This ensures security professionals can meet compliance requirements and developers can integrate protection without derailing product timelines.

Making strong security simple

Mobile application security cannot remain an afterthought, especially in industries where sensitive data, financial transactions, or intellectual property are at stake. Manual approaches to runtime protection are no longer sufficient, both because they are too resource-intensive and because they create predictable patterns that attackers can exploit. Automated RASP injection changes this equation. By randomizing and distributing checks across application code and dependencies, Guardsquare ensures that protections evolve with each build, invalidating attacker analysis and raising the baseline of security for every release.

For developers, this means less time spent writing and maintaining security code, and more time building features. For security professionals, it means stronger assurance that applications in production are resilient against both static and dynamic threats. With automated RASP injection, strong security and fast development no longer need to be at odds, they can finally advance together.

Learn more about automated RASP injection to protect your mobile apps from threats. Connect with our experts.