Short answer: They can be – but not always. Document scanning apps are incredibly convenient (snap a receipt or passport, OCR it to searchable text, upload to the cloud), but they also handle very sensitive information and have a few well-documented risks. With a little knowledge and a simple checklist you can keep your documents private and secure.
Below we’ll explain how scanner apps work, the main risks (with real examples), the legal/regulatory angle (especially for UK/EU users), and a practical checklist for choosing and using a scanning app safely.
How document scanning apps actually work (so you know what could go wrong)
Most modern document scanner apps do three things:
- Use your phone camera to take a “scan” (an image).
- Optionally run OCR (optical character recognition) to extract searchable/editable text from the image.
- Store the image and/or text locally and/or upload it to cloud storage (their servers, Google Drive, iCloud, Dropbox, etc.) and may send data to third-party analytics/ad providers.
That chain: Image → OCR → storage → sharing is where vulnerabilities appear: malware in the app, insecure uploads, third-party SDKs collecting data, or overly broad app permissions on your device. The European Data Protection Board has highlighted specific risks around OCR systems and the sensitive personal data they can expose. edpb.europa.eu
Real-world wake-up call: CamScanner (malicious module found)
A high-profile example: in 2019 researchers found a malicious advertising module in a widely-used Android scanner app (CamScanner) that could download additional malicious files and perform unwanted actions. Google temporarily removed the app while the issue was fixed. That case shows two things: 1) even popular apps can carry dangerous third-party code, and 2) vendors sometimes remove the risk – but only after detection.1
Main risks explained
1. Malicious or compromised code inside the app
Third-party ad/analytics SDKs or compromised libraries can introduce malware or data exfiltration. This is exactly what happened in the CamScanner incident. kaspersky.com
2. Unnecessary or overbroad permissions
Scanner apps need camera and storage access, but some request extra permissions (location, contacts, microphone) that aren’t strictly necessary. Those extra permissions widen the attack surface and data collected. A recent consumer analysis of mobile apps shows how common excessive permissions are across popular apps.2
3. Cloud uploads and retention
Many apps upload your scans to cloud servers (for backup, OCR, or sharing). If the app provider’s storage is insecure or their privacy policy allows broad use of your data, your scans (IDs, financial docs, passports) could be exposed, retained indefinitely, or processed by third parties. Check whether uploads are encrypted and where the servers are located. Guidance on appropriate security measures is available from regulators.3
4. OCR + sensitive information
OCR turns images into text. That’s incredibly useful, but it also creates machine-readable copies of extremely sensitive data (names, numbers, addresses, sometimes biometric identifiers on IDs). Regulators warn that such processing should be carefully assessed and documented.4
5. Biometric and identity risks
Scans of passports, driver’s licences or ID cards may include biometric data or identifiers that trigger heightened legal protections (especially in the EU/UK). Organisations using scanned data must apply GDPR principles and, in some cases, perform Data Protection Impact Assessments. The UK Information Commissioner’s Office (ICO) provides guidance on security outcomes and biometric processing.5
Legal & regulatory quick notes (UK / EU / US)
- UK / EU (GDPR / UK-GDPR): If you’re a business or handling personal data of others, GDPR applies – you must use appropriate technical and organisational measures when processing personal data (including scans). The ICO’s guidance on data security is the right place to start.3
- USA (FTC): The Federal Trade Commission expects businesses to implement reasonable data-security practices and has long published best-practice guidance for protecting personal information.6
If you’re scanning your own receipts at home, the legal obligations are low, but the security risks (identity theft, exposure of financial details) still matter — so apply the same common-sense controls.
Practical checklist: How to choose and use a scanning app safely
Before you install
- Prefer built-in options first. Both iOS and Android/Google offer built-in document scanning that stores files in iCloud/Google Drive — these are often better maintained and monitored than small third-party apps. (Built-in options keep fewer moving parts and fewer third-party SDKs.)
- Check app store reputation & reviews. Look for long-term, consistent maintenance and recent updates.
- Read the privacy policy (quick scan). Does the app upload files by default? Do they state whether they process or retain scans? If the policy is unclear, assume the app may retain or use data.
- Research the developer. Known, reputable companies are safer than obscure startups with little track record.
App permissions & settings
- Only allow camera + file access. Deny location, microphone, contacts unless the app explicitly needs them for a clear reason.
- Disable cloud backup by default. If the app auto-uploads scans to its cloud, turn that off unless you understand the provider’s security.
- Use device storage (local) when possible. Scan to local files first, then move to trusted storage (your encrypted drive, secure cloud you control).
While scanning
- Avoid scanning highly sensitive documents into untrusted apps. For passports, national IDs, or signed legal documents, prefer trusted systems or a trusted scanner on a secured computer.
- Blur or redact unnecessary data before uploading/sharing if you only need parts of a document.
After scanning
- Check retention & delete promptly. If an app stores copies on their servers, delete the cloud copies and revoke app permissions when you no longer need them.
- Export to a secure place. Move important scans to an encrypted folder, a password-protected archive, or a secure cloud you control (with strong 2FA).
- Keep software updated. App and OS updates patch vulnerabilities.
For businesses
- Do a DPIA (Data Protection Impact Assessment) if processing sensitive IDs or biometric info. ICO and EDPB materials explain when these are necessary.7
- Contractual safeguards: Ensure your vendor contract requires encryption at rest/in transit, limited retention, and no sharing with third parties except with your consent.
Specific technical things to look for in an app’s security posture
- Encryption in transit (TLS/HTTPS) and at rest.
- Zero-knowledge or client-side encryption (best practice: provider can’t read your files).
- SOC2 / ISO 27001 or equivalent certificates for the vendor (signals mature security practices).
- Transparent data retention policy (how long do they keep scans?).
- Third-party SDK disclosure (be wary if they don’t list analytics/ads providers).
Honest advice on app choices
We’re deliberately cautious about naming a single “best” third-party scanner because vendors and their privacy practices change often. Instead:
- Prefer built-in OS scanners (iOS Notes / Apple’s scanner; Google Drive or Google Photos scanning) for routine receipts and notes.
- For business workflows, use enterprise tools (your company’s MDM-approved scanners, paid services with strong contracts and certifications).
- If you use a third-party app, pick a vendor with clear privacy commitments and good security attestations – and follow the checklist above.
Bottom line (what to do right now)
- Use a built-in or trusted scanner for routine docs.
- Turn off automatic cloud uploads unless you understand the provider’s security.
- Keep scans local, export to an encrypted folder you control, and delete unnecessary copies.
- Limit app permissions to camera and local files.
- For business or highly sensitive documents, use enterprise-grade solutions and follow the ICO/GDPR guidance (DPIA, contracts, encryption).
- https://www.kaspersky.com/blog/camscanner-malicious-android-app/28156/ [↩]
- https://www.thetimes.co.uk/article/smartphone-apps-data-demands-pose-risk-to-privacy-experts-warn-dspwdnpbh/ [↩]
- https://ico.org.uk/for-organisations/uk-gdpr-guidance-and-resources/security/a-guide-to-data-security/ [↩] [↩]
- https://www.edpb.europa.eu/system/files/2024-06/ai-risks_d2optical-character-recognition_edpb-spe-programme_en_2.pdf [↩]
- https://ico.org.uk/for-organisations/uk-gdpr-guidance-and-resources/lawful-basis/biometric-data-guidance-biometric-recognition/how-do-we-demonstrate-our-compliance-with-our-data-protection-obligations/ [↩]
- https://www.ftc.gov/business-guidance/resources/protecting-personal-information-guide-business-0 [↩]
- https://ico.org.uk/for-organisations/uk-gdpr-guidance-and-resources/security/a-guide-to-data-security/security-outcomes/ [↩]