Mobile Healthcare Press Release

Mobile Health Apps Systematically Expose PII and PHI Through APIs

Report Reveals API-Focused Mobile Attacks Exploit Vulnerabilities Such as BOLA to Expose Patient PII and PHI, and the Pandemic-Driven Uptick in mHealth App Usage Exposes Millions of Patients’ Data.

SAN JOSE, CA and EDINBURGH, UK, February 9, 2021 - Approov, creators of advanced API threat protection for mobile applications, today released findings revealing that fully 100 percent of the 30 popular mHealth apps analyzed by Alissa Knight, partner at Knight Ink, are vulnerable to API attacks that can allow unauthorized access to full patient records including protected health information (PHI) and personally identifiable information (PII). The study underscores the API shielding actions now urgently required to protect mHealth apps from API abuse.

The Knight Ink vulnerability research study, “All That We Let In” details findings, and also notes that the results are particularly worrisome given the increased reliance on mHealth apps during the global pandemic, which in turn is drawing threat actors to mHealth apps as an attack surface of choice. Observers with Pew Research noted that mHealth apps are now generating more user activities than other mobile device apps such as online banking and job searching. Observers also note that patient IDs and PHI are more lucrative in dark web markets than credit card data.

Alissa Knight, researcher and author of the report said, “Look, let’s point the pink elephant out in the room. There will always be vulnerabilities in code so long as humans are writing it. Humans are fallible. But I didn’t expect to find every app I tested to have hard-coded keys and tokens and all of the APIs to be vulnerable to broken object level authorization (BOLA) vulnerabilities allowing me to access patient reports, x-rays, pathology reports, and full PHI records in their database. The problem is clearly systemic.”

The study tested 30 popular mHealth apps. The average number of downloads for each app tested was 772,619, and Knight Ink estimates that the 30 apps evaluated expose some 23 million mHealth users, at a minimum. Analysts expect that the total number of users exposed by the 318,000 mHealth apps now available on major app stores is likely far greater.

Among key report findings, these basic vulnerabilities open the door for hackers:

  • Of the 30 popular apps Knight Ink tested, 77 percent contained hardcoded API keys, some which don’t expire, and seven percent contained hardcoded usernames and passwords. Seven percent of the API keys belonged to third-party payment processors that warn against hard-coding their secret keys in plain text.
  • 50 percent of the APIs tested did not authenticate requests with tokens.
  • API keys and tokens were discovered for Google,, Braze, Tune, Optimizely, Cisco Umbrella, Microsoft App Center, Bugsnag, Contentful, Stripe, Amazon AWS, Radaee, Sendbird, AppsFlyer, Facebook, Vonage, SalesForce and Mparticle.

If a record is exposed, don't expect privacy:

  • 50 percent of the records accessed contained names, social security numbers, addresses, birthdates, allergies, medications, and other sensitive data for patients.

If one patient's records can be accessed, often many others can be accessed indiscriminately:

  • 100 percent of API endpoints tested were vulnerable to BOLA attacks that allowed the researcher to view the PII and PHI for patients that were not assigned to the researcher’s clinician account.
  • 50 percent of the APIs tested allowed medical professionals to access the pathology, x-rays, and clinical results of other patients (see study findings - Exhibits N, O and P of the study findings).
  • A replay vulnerability allowed the researcher to replay days-old FaceID unlock requests that allowed her to take over other users’ sessions.

Even if the app and records are well protected, communication between them is easily breached:

  • 100 percent of the apps tested failed to implement certificate pinning, enabling the researcher to perform woman-in-the-middle attacks against the app to observe and manipulate records (see study findings - Exhibit J).

The findings demonstrate that the security standards required for compliance with U.S. government FHIR/SMART standards merely represent a subset of the steps needed to secure mobile apps and the APIs which enable apps to retrieve data and interoperate with data resources and other applications.

Approov Founder and CEO David Stewart said, “These findings are disappointing but not at all surprising. The fact is that leading developers and their corporate and organizational customers consistently fail to recognize that APIs servicing remote clients such as mobile apps need a new and dedicated security paradigm. Because so few organizations deploy protections for APIs that ensure only genuine mobile app instances can connect to backend servers, these APIs are an open door for threat actors and present a real nightmare for vulnerable organizations and their patients.”

The report recommends that mHealth platform developers - and all developers and organizations using mobile applications - adopt several key steps to protect their customer data and sensitive resources, including:

  • Address both app security and API security: recognize that synthetic traffic to the API is an issue and arises from bots and automated tools, not from genuine apps and legitimate data requests.
  • Shift left and shield right: secure the development process and harden apps, but ensure that run-time protection is also in place.
  • Protect against X-in the middle attacks: certificate pinning is critical but often left undone because expired certificates can block apps and impact the customer’s experience. However, when done correctly, certificate pinning does not impact either performance or availability.
  • Improve visibility into controls: organizations and developers need to monitor the effectiveness of the controls they implement and adjust them easily – both for compliance with HIPAA mandates and to sustain data security and privacy.
  • Penetration testing and static and dynamic code analysis should be performed regularly.

To download a free copy of the complete study, go to

About Approov

Approov solutions help stop API abuse at the edge, and prevent security breaches in mobile channels. With more businesses moving to digitalization and future-ready services that utilize mobile API connections, securing those connections properly can get overlooked or not fully implemented for all possible threats, exposing organizations and their users to breaches, fraud, denial of service, and other forms of API abuse. Knight Ink found that the Approov solution was effective in preventing 100% of the unauthorized API requests described in the report.

Approov API Threat Protection provides a multi-factor, end-to-end mobile API security solution that complements identity management, endpoint, and device protection to lock-down proper API usage. It ensures that only safe and approved apps running in safe environments can successfully and securely access an organization’s APIs, and turns away unauthorized accesses by attacker scripting, bots and fake or tampered apps.

About Knight Ink

Knight Ink is a content strategy, creation, and influencer marketing agency founded for category leaders and challenger brands in cybersecurity to fill current gaps in content creation. We help vendors create and distribute their stories to the market in the form of written and visual storytelling drawn from 20+ years of experience as hackers to tell a unique story through the lens of an adversary. Knight Ink balances pragmatism with thought leadership that amplifies a brand’s reach, breeds customer delight and loyalty, and delivers creative experiences in written and visual content in cybersecurity.

Additional Resources:

Research Report - All That We Let In:

Infographic – All That We Let In: (Facts on Vulnerabilities in Mobile Health Apps and APIs)

Approov mHealth blog - Exposing Vulnerabilities in mHealth Apps and APIs:

Approov healthcare case study - How MV Healthcare Uses Approov to Give Flexibility to Physicians while Protecting Patient Data:


Media Contact:

Dan Chmielewski
Madison Alexander PR, Inc.
C: 949-231-2965

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