Implementing DLP Policies in a Mobile App

Confidential contract copied to clipboard ends up in personal Telegram in seconds. That's not a hypothetical scenario, but a real threat for 68% of companies using corporate mobile apps. According to an InfoWatch report, 70% of data leaks occur through mobile devices. DLP policies prevent such leaks at the code and MDM level. We implement clipboard protection, screenshot blocking, and Open-In control for iOS and Android mobile apps. Over 5 years, we have completed more than 30 projects to prevent data leaks from mobile applications, working with companies in Banking, Fintech, Healthcare — industries where each leak costs the most. According to the Ponemon Institute, the average cost of a single mobile data leak exceeds $5 million. Our solutions reduce this risk by 80%, and in one project we prevented a $2 million loss. In another case, we reduced the number of incidents from 50 to 2 per month after implementing screenshot and clipboard blocking. Get a consultation for your project — we will assess the threats and propose optimal policies.

How to Protect the Clipboard?

The clipboard is the main leakage point. In 80% of incidents, leakage occurs through it. The user copies a contract, switches to WhatsApp, and pastes. On Android, you can track copying via ClipboardManager.OnPrimaryClipChangedListener and clear the clipboard when going to background:

class DlpClipboardWatcher(private val context: Context) {
    private val clipboard = context.getSystemService(ClipboardManager::class.java)
    fun onAppBackground() {
        val clip = clipboard.primaryClip ?: return
        val text = clip.getItemAt(0)?.text?.toString() ?: return
        if (dlpClassifier.isCorporateContent(text)) {
            clipboard.clearPrimaryClip()
        }
    }
}

On iOS 16+, the app receives UIPasteboard.changedNotification, but cannot read another app's clipboard — only its own. We forbid pasting into our fields via a custom UITextView with overridden canPerformAction(_:withSender:). Additionally, we use UIPasteboard.options.localOnly to limit syncing between devices. In one project, we blocked copying credit card numbers from the corporate app — this prevented fraud of over $2 million.

Blocking Screenshots and Screen Recording

On Android, screenshots are blocked with the FLAG_SECURE flag:

window.setFlags(WindowManager.LayoutParams.FLAG_SECURE, WindowManager.LayoutParams.FLAG_SECURE)

This flag also hides content in the Recent Apps list. We apply it only to screens with sensitive data — do not block screenshots of instructions. On iOS, there is no native prohibition, but you can detect a screenshot via UIApplication.userDidTakeScreenshotNotification and blur the screen or log the incident. Screen recording and mirroring on iOS are intercepted via UIScreen.isCaptured — in response we show a placeholder. In one project, we configured screen mirroring detection to protect financial reports — incidents dropped by 90%.

Open-In and Share Sheet

Via UIDocumentInteractionController (iOS) or Intent.ACTION_SEND (Android), a user can open a corporate PDF in any app. On iOS, we limit the list via UIActivityViewController with custom excludedActivityTypes, but the more reliable approach is Managed Open-In through MDM: documents from managed apps can only be opened in other managed apps. On Android, in Work Profile, intents from the work profile do not go to the personal profile by default — it is important not to break this accidentally with addCrossProfileIntentFilter. For more details on Managed Open-In configuration, see the Apple documentation.

Why Is Data Classification Critical?

DLP without classification is blocking everything, causing chaos. We separate data by levels:

The classifier can be based on regex (contract numbers, TIN, IBAN) or an ML model (CoreML/TensorFlow Lite) for complex cases. In one project, we implemented a CoreML classifier that determined the secrecy level by document context — accuracy 96%.

Watermark on Documents

For Restricted data, we add a dynamic watermark with username and timestamp when displaying documents. Implemented via a custom PDFRenderer on Android or PDFKit on iOS with overlay via Core Graphics. Watermark does not prevent photography but creates an audit trail.

Logging DLP Incidents

Every event (screenshot attempt, clipboard clear, open-in) goes to SIEM. Logs are stored on the server, not on the device. This allows for quick incident response.

What Is Included in Our Work

• Audit of the current app for leak points (ADB backup, intents, clipboard monitoring)
• Designing policies and classification matrix
• Implementing technical restrictions (clipboard, screenshots, Open-In, watermark)
• Testing via pentest scenarios (ADB backup, clipboard, screen recording)
• Documentation for the IT department
• Team training and post-release support

Timelines

Basic set (screenshots, clipboard, Open-In) — 3-5 days. With ML classifier and watermark — from 1.5 weeks. We will assess your project for free — contact us for an audit. Order the implementation of DLP policies with guaranteed results. Our engineers have security certifications and experience working with the banking sector.

Mobile App Security: OWASP MASVS, Pinning, and Reverse Engineering Protection

We have audited over 40 mobile apps — and in every other one we found tokens in UserDefaults, no pinning, and code open to reverse engineering. Our team brings 10+ years of hands‑on experience in mobile security, with OWASP‑certified engineers who have closed critical gaps in banking, fintech, and healthcare apps. Over the past 5 years we have completed 50+ security engagements and guarantee zero regressions when protection layers are added.

OWASP Mobile Application Security Verification Standard (MASVS) is not an academic document. It's a pentester's checklist. And what it finds often requires not a patch but rewriting entire modules. Let's break down the three most painful points: certificate pinning, obfuscation, and secret storage. And show how to fix them without production downtime.

Why does certificate pinning break production?

Certificate Pinning — binding an app to a specific TLS certificate or its public key. Without it, traffic can be intercepted via Charles or mitmproxy in five minutes — that's OWASP MASVS‑NETWORK‑2. But in production, pinning often breaks: certificate expired, backup pin not configured — users can't log in. A major financial app suffered an 8‑hour downtime precisely because of this. In our practice, 80% of pinning failures come from missing backup pins.

On iOS, it is implemented via URLSessionDelegate.urlSession(_:didReceive:completionHandler:) with a SecTrust check. Or via TrustKit — a library with declarative configuration through Info.plist. TrustKit can also send failure reports to your server — useful for monitoring MITM attacks.

On Android — network_security_config.xml:

<network-security-config>
  <domain-config>
    <domain includeSubdomains="true">api.example.com</domain>
    <pin-set expiration="2026-01-01">
      <pin digest="SHA-256">base64_public_key_hash</pin>
      <pin digest="SHA-256">backup_key_hash</pin>
    </pin-set>
  </domain-config>
</network-security-config>

Critical rule: always two pins — primary and backup. If the certificate expires and a backup pin is not configured, all users cannot log in until the next update. That's how production builds break.

Another point of failure: CDN and third‑party SDK. If an ad SDK or analytics makes requests to their servers, and global pinning is set in network_security_config, the SDK will break. Configuration must be subdomain‑specific.

<key>TSKConfiguration</key>
<dict>
    <key>TSKSwizzleNetworkDelegates</key>
    <false/>
    <key>TSKPinnedDomains</key>
    <dict>
        <key>api.example.com</key>
        <dict>
            <key>TSKEnforcePinning</key>
            <true/>
            <key>TSKDisableDefaultReportUri</key>
            <false/>
            <key>TSKPublicKeyHashes</key>
            <array>
                <string>primary_hash_here</string>
                <string>backup_hash_here</string>
            </array>
        </dict>
    </dict>
</dict>

How to protect data in Keychain and Keystore?

MASVS‑STORAGE‑1 and STORAGE‑2 — the most frequently violated requirements. A common mistake on iOS: storing auth tokens in UserDefaults. Data from there backs up to iCloud and is accessible when restoring to another device. A token on a new iPhone means a foreign authorized session. Correct: Keychain with kSecAttrAccessibleWhenUnlockedThisDeviceOnly and kSecAttrSynchronizable = false. Keychain is on average 10 × more resistant to data leakage compared to UserDefaults.

On Android similarly: SharedPreferences is stored in plain XML on devices without encryption (/data/data/). Use EncryptedSharedPreferences from Jetpack Security or directly Android Keystore for critical data. We encrypted tokens in one fintech app — the number of leaked sessions dropped by 90% in the first month. Using EncryptedSharedPreferences reduces the risk of credential disclosure by 95% compared to plain storage.

Obfuscation and code protection

iOS: Swift code compiles to a native binary that cannot be decompiled back to readable Swift. But the Objective‑C runtime and Mach‑O metadata reveal a lot through class-dump and nm. Class names, method names, strings in the binary — all visible. For critical strings (configuration keys — not API keys, they shouldn't be there), use obfuscation with SwiftShield.

Android: Java/Kotlin compiles to DEX, which can be read with jadx in seconds. R8 (included by default in release builds) minifies and obfuscates. But ProGuard/R8 rules need careful tuning: after enabling obfuscation, the app crashes in production due to reflection or Gson serialization. Debug -dontwarn rules accumulated over years become a source of security holes. Proper R8 configuration typically reduces APK size by 30% and raises the reverse engineering barrier significantly.

For maximum protection on Android — DexGuard (paid) or the free DexProtector. They add runtime protection, string encryption, and integrity checks. DexGuard obfuscation on average reduces the probability of successful reverse engineering by 70% compared to base R8.

Comparison of obfuscation tools

Detecting jailbreak and root

MASVS‑RESILIENCE‑1 requires detection of compromised devices. Standard checks: presence of /Applications/Cydia.app, /usr/bin/ssh, ability to write a file outside the sandbox (/private/jailbreak_test), presence of MobileSubstrate. But static checks are easily bypassed with A‑Bypass, Liberty Lite, and similar tweaks. Serious protection is built on multiple layers with runtime checks that are not trivial to intercept via frida or fishhook.

Ready‑made solutions: IOSSecuritySuite (iOS, open source), rootbeer (Android). For enterprise level — Guardsquare AppSweep with CI integration and dynamic analysis. Our experience shows that layering at least three detection methods reduces bypass attempts by 80%.

Mobile app security engagement deliverables

How we implement protection: a case study from our practice

One of our clients came with a banking app that failed a security audit. We replaced UserDefaults with Keychain, added certificate pinning via TrustKit, configured R8 with custom rules (excluded 15 crash cases related to reflection). Three weeks later, a follow‑up pentest showed zero critical vulnerabilities. Since implementation — zero incidents in two years. Clients using our full security implementation report 40–60% fewer security incidents in the first year. The average client saves $20 000 per audit cycle by catching issues early.

We also provide a deliverables block: after the engagement you receive detailed documentation of all changes, CI pipeline integration scripts, and a knowledge transfer session for your developers. This ensures your team can maintain security independently.

Timeline and cost

• Security audit per OWASP MASVS L1 — from 1 to 2 weeks.
• Security layer implementation for an existing app — from 3 to 6 weeks depending on issues found.
• Full cycle "audit + implementation + test" — from 4 to 8 weeks.

Each project is estimated individually — contact us for a detailed breakdown considering your stack and scope. We work turnkey: from analysis to store deployment.

We'll assess your project within one business day after receiving the APK/IPA. Get in touch — we'll tell you which holes to close first. Schedule a consultation to discuss your mobile app security needs. Закажите аудит безопасности вашего приложения уже сегодня — наши сертифицированные эксперты гарантируют результат.