CVE-2020-25183

Executive Summary

CVE-2020-25183 is an improper authentication vulnerability in the Medtronic MyCareLink Smart 25000 Patient Reader, a Bluetooth-connected home monitoring device used with implantable cardiac devices. The flaw resides in the authentication protocol between the MCL Smart Patient Reader and the MyCareLink Smart mobile application, allowing an attacker with a second mobile device or malicious app on the patient's smartphone to bypass authentication and impersonate the legitimate Medtronic application within Bluetooth range. With a CVSS score of 8.0, successful exploitation could allow an attacker to interact with the patient's medical monitoring device, potentially accessing sensitive patient health data or interfering with device communications. Medtronic has released a firmware update distributed through mobile application version 5.2, along with enhanced integrity validation and device monitoring controls.

Technical Analysis

The Medtronic MyCareLink Smart 25000 is a home-based patient reader designed to communicate with implantable cardiac devices (ICDs and pacemakers) via short-range telemetry, then relay data to healthcare providers through the patient's smartphone using Bluetooth communication. The vulnerability class is improper authentication (CWE-287): the protocol used to authenticate between the Patient Reader and the Medtronic MyCareLink Smart mobile app contains a bypassable authentication mechanism.

Vulnerability mechanism: The MyCareLink Smart Patient Reader relies on the mobile application to establish a trusted session over Bluetooth. The authentication protocol fails to adequately verify that the connecting device is the legitimate, unmodified Medtronic application. An attacker can exploit this by using either a separate mobile device or a malicious application installed on the patient's own smartphone. The malicious component mimics the legitimate application's authentication handshake and fools the Patient Reader into believing it is communicating with the original Medtronic app. The attack is executed when the attacker is within Bluetooth communication range of the Patient Reader — approximately 10 meters (33 feet) for typical Bluetooth Class 2 devices.

Attack surface: The primary attack surface is the Bluetooth interface of the MCL Smart Patient Reader (model 25000). Secondary attack surface includes the patient's smartphone if the attacker can coax the victim into installing a malicious application. The attack requires proximity (Bluetooth range) but does not require physical access to the device or any credentials (according to the CVSS vector, no privileges or user interaction required beyond installation of the malicious app in the second scenario).

Technical detail limitations: The NVD description does not specify the exact authentication mechanism, cryptographic implementation, or specific protocol messages involved. Insufficient technical detail is available publicly to document the precise bypass technique (e.g., whether it involves replay, weak session tokens, missing certificate pinning, or improper challenge-response validation). The vulnerability class-level mechanism — authentication bypass via protocol manipulation — is the extent of confirmed technical information.

Mitigating controls added by Medtronic: The vendor has deployed Enhanced Integrity Validation (EIV) technology for early detection and real-time mitigation of known exploit attempts, and an advanced detection system enabling device-level logging and monitoring of all device activity.

Exploitation Scenarios

The attack chain below is inferred from the vulnerability class (Bluetooth authentication bypass) and the NVD description. No public PoC is available; attack chain is inferred from vulnerability class and the CNA description.

Reconnaissance and target identification (Step 1): An attacker identifies a victim with an implantable cardiac device and a MyCareLink Smart Patient Reader in their home. Reconnaissance can include physical surveillance to confirm the device's presence, or war-driving/war-walking with a Bluetooth scanner to detect the "MCL Smart" or "MyCareLink" Bluetooth advertising name within range. The attacker needs to be within Bluetooth range only during the exploitation window — typically 10 meters of the patient's home.

Triggering the flaw (Step 2): The attacker either (a) pairs their own mobile device with the Patient Reader, or (b) convinces the victim to install a malicious application that contains a forged version of the Medtronic authentication client. When the attacking device initiates the Bluetooth connection and performs the authentication handshake, the Reader's improper authentication check is bypassed — the device's integrity validation fails to detect that the connecting party is not the genuine Medtronic application.

Payload/execution at vulnerability-class level (Step 3): The attacker's malicious application or device completes the authentication exchange successfully, thereby establishing a session with the Patient Reader as if it were the legitimate MyCareLink Smart app. At this point, the attacker gains the same access and privileges as the genuine application — reading data from the Patient Reader, potentially issuing commands to the Reader that it would relay to the implant, or exfiltrating data that the Reader has collected from the implantable device. Note: the extent of command capability is not fully detailed in public sources; the confirmed impact is unauthenticated access to the Reader/patient data.

Post-exploitation impact (Step 4): The attacker can potentially:

• Read sensitive cardiac data (heart rhythm recordings, device diagnostics) that the Patient Reader has captured from the implant, creating a patient-privacy breach and potential for blackmail or identity theft.
• Interfere with normal monitoring communications, potentially delaying or blocking legitimate data transmission to healthcare providers — a patient-safety concern.
• In a worst-case scenario, if command relay capabilities exist, issue unauthorized operations to the implantable device (though the NVD description does not confirm write/command capability; this remains speculative at this level).

Notable constraint: The attack window is physically limited by Bluetooth range, and the attack is opportunistic rather than remotely practical. However, the CVSS vector (AV:A/AC:L/PR:N/UI:N) indicates a low-complexity, no-privilege attack that can be performed repeatedly if the attacker remains in range.

Impact Assessment

Business Impact: CVE-2020-25183 affects medical device security, which carries higher stakes than typical IT vulnerabilities. Exploitation creates three classes of impact: (1) Patient privacy breach — access to sensitive cardiac health data captured by the Patient Reader; (2) Patient safety risk — potential interference with monitoring data flow, which could delay critical alerts to healthcare providers or alter the data clinicians rely on for treatment decisions; (3) Regulatory and liability exposure — healthcare providers and Medtronic face potential regulatory scrutiny under medical device cybersecurity frameworks, with reputational damage if exploited.

CVSS sub-score analysis: Base score 8.0 (High). The vector reflects: Attack Vector = Adjacent (Bluetooth range required — restricts remote attackers but still feasible with proximity), Attack Complexity = Low (no special conditions required), Privileges Required = None, User Interaction = None (for the device-pairing scenario; the malicious app scenario requires victim installation but counts as non-interactive once installed), Confidentiality Impact = High (full access to patient health data), Integrity Impact = High (the device can be made to believe it's communicating with the legitimate app, enabling data manipulation). Availability Impact = None, per the vector.

Affected systems and blast radius: The blast radius is confined to patients with the Medtronic MyCareLink Smart 25000 Patient Reader paired to a smartphone running the MyCareLink Smart app. EPSS score of 0.00787 (52.8th percentile) indicates the vulnerability is not being widely exploited, and the device is not listed on CISA's Known Exploited Vulnerabilities catalog. However, the high CVSS score and the sensitive nature of the data warrant immediate patching priority for any identified systems.

Detection Guidance

Sigma Rule

title: Suspicious Bluetooth Authentication Attempts to Medtronic MyCareLink Device
id: 1e029c7a-3f51-4c68-9d2e-c50f3d44a1a9
status: experimental
description: Detects repeated failed or rapid paired Bluetooth connections to a Medtronic MyCareLink Smart Patient Reader, or connections from unexpected device names within proximity.
author: Valtersit Threat Intel
date: 2024/05/01
tags:
    - attack.t1190
    - attack.collection
    - cve.2020-25183
logsource:
    product: mobile_device
    category: bluetooth
detection:
    selection:
        device_name: 
            - "MyCareLink"
            - "MCL Smart"
            - "Medtronic*"
        event_type: 
            - "pairing_request"
            - "connection_established"
            - "authentication_failure"
    condition: selection
    timeframe: 15s
    condition: selection | count() by src_device > 3
falsepositives:
    - Legitimate re-pairing after phone OS update or app reinstall
    - Multiple family members synchronizing devices
level: medium

YARA Rule

rule Medtronic_MyCareLink_Auth_Bypass_CVE_2020_25183
{
    meta:
        author = "Valtersit Threat Intel"
        description = "Detects artifacts of Medtronic MyCareLink authentication bypass exploitation - malicious APK bundling forged auth client"
        date = "2024-05-01"
        cve = "CVE-2020-25183"
        score = 60
    strings:
        $auth_flow_1 = "authenticateReader" ascii nocase
        $auth_flow_2 = "session_token" ascii nocase
        $auth_flow_3 = "pairDevice" ascii nocase
        $app_marker_1 = "com.medtronic.mycarelinksmart" ascii nocase
        $app_marker_2 = "MyCareLink Smart" ascii
        $app_marker_3 = "MCLSmart" ascii
        $bt_marker = "BluetoothGatt" ascii nocase
        $bt_uuid = "0000fef5" ascii   // Example Bluetooth service UUID pattern
    condition:
        (uint16(0) == 0x5A4D or uint32(0) == 0x04034B50) and // MZ or ZIP (APK)
        2 of ($auth_flow_*) and
        2 of ($app_marker_*) and
        $bt_marker
}

Suricata IDS Rule

Suricata operates on network traffic. Since this exploit occurs over Bluetooth (non-IP) and/or locally between app and device, network-level detection is limited. The following rule monitors for anomalous traffic from devices advertising as Medtronic over Bluetooth-paired IP connections (e.g., telemetry data exfiltration to a C2).

alert ip any any -> any any (msg:"Medtronic MyCareLink CVE-2020-25183 - Anomalous Bluetooth-paired data exfiltration attempt"; 
  content:"MCL"; nocase; depth:20; 
  content:"read_telemetry"; nocase; within:100;
  content:"|0d 0a|"; within:200;
  sid:10004183; rev:1; classtype:trojan-activity; 
  reference:cve,2020-25183;)

Elastic Detection

// Detect repeated pairing requests to Medtronic devices within short timeframe
// from different MAC addresses (potential rogue device spoofing)
sequence by bt_device_name with maxspan=1m
  [any where bt_device_name : ("MyCareLink*", "MCL Smart*") and event.action == "pairing_request"]
  [any where bt_device_name : ("MyCareLink*", "MCL Smart*") and event.action == "connection_established"]
  [any where bt_device_name : ("MyCareLink*", "MCL Smart*") and event.action == "pairing_request"]
  [any where bt_device_name : ("MyCareLink*", "MCL Smart*") and event.action == "pairing_failed_or_auth_error"]

Splunk SPL Query

index=bluetooth OR index=endpoint 
  (device_name="MyCareLink*" OR device_name="MCL Smart*" OR product="Medtronic*")
  (event="pairing_request" OR event="authentication_failure" OR event="connection_established")
  | stats count, dc(src_mac) as unique_sources, values(src_mac) as src_macs by device_name, src_device
  | where unique_sources > 2 OR count > 5
  | eval alert = if(unique_sources > 2 OR count > 5, "POSSIBLE_AUTH_BYPASS_ATTEMPT", "monitor")

Wazuh OSSEC Rule

<group name="bluetooth,">
  <rule id="100183" level="10">
    <decoded_as>bluetooth_auth</decoded_as>
    <match>authentication failed</match>
    <match>MyCareLink</match>
    <if_sid>parent_bluetooth_rule</if_sid>
    <description>CVE-2020-25183: Repeated Bluetooth authentication failures against Medtronic MyCareLink Smart Patient Reader - possible authentication bypass attempt.</description>
    <group>attack.t1190,</group>
    <options>no_full_log</options>
  </rule>

  <rule id="100184" level="12">
    <decoded_as>bluetooth_auth</decoded_as>
    <match>connection established from unknown device</match>
    <match>MyCareLink</match>
    <if_sid>parent_bluetooth_rule</if_sid>
    <time>60</time>
    <field name="occurrences">3</field>
    <description>CVE-2020-25183: Multiple successful connections from unrecognized devices to Medtronic MyCareLink Smart Patient Reader - possible spoofing of legitimate app.</description>
    <group>attack.t1190,</group>
  </rule>
</group>

Mitigation & Patch Guidance

Patch confidence: 2/4 (CLAIMED) — single source (CNA) claims patch is available; not independently confirmed by third-party researchers or public testing.

1) Immediate mitigations (no patch applied yet):

• Maintain strict physical control over the home monitor. Use only in private, physically controlled environments (home, apartment, secured facility).
• Only use home monitors obtained directly from your healthcare provider or a Medtronic representative — avoid second-hand or resold devices.
• Keep the smartphone operating system current (iOS 10+, Android 6.0+ minimum; preferably latest version available).
• Do not install untrusted or third-party applications on the smartphone paired with the Patient Reader. Treat this phone as a dedicated medical device.
• Document any unusual behavior of the Patient Reader or mobile app (unexpected disconnections, re-pairing prompts, unknown devices appearing in Bluetooth scan) and report to healthcare provider or Medtronic representative.

2) Patch/upgrade steps:

• Update the MyCareLink Smart mobile application to version 5.2 or later via the official Apple App Store or Google Play Store.
• Ensure smartphone OS meets minimum version requirement (iOS 10+ / Android 6.0+) — if not, update the OS first.
• After updating the app, the Patient Reader firmware is automatically updated on next use — confirm the Reader remains powered and connected until update completion.
• Verify successful update by checking app version and confirming no pending update notifications.
• If the firmware update cannot be applied (e.g., unsupported smartphone), contact Medtronic for alternative update methods or device replacement.

3) Long-term hardening:

• Monitor Bluetooth pairing activity: maintain awareness of all devices paired with the Patient Reader; periodically review paired device list in the mobile app or via Bluetooth settings.
• Enable and review the device-level logging provided by Medtronic's advanced detection system, if available in the app/device menu.
• Follow Medtronic security bulletins at: https://www.medtronic.com/xg-en/product-security/security-bulletins.html
• Healthcare provider organizations should inventory all patients using MyCareLink Smart devices, track patch compliance, and incorporate this CVE into medical device security policies.
• Consider substituting with a medical device gateway or network isolation if the Patient Reader must be placed in a semi-public environment (e.g., long-term care facility).

References

1. NVD Entry: https://nvd.nist.gov/vuln/detail/CVE-2020-25183
2. Medtronic Product Security Bulletin: https://www.medtronic.com/xg-en/product-security/security-bulletins.html
3. Medtronic Product Security Portal: https://www.medtronic.com/security
4. CISA Known Exploited Vulnerabilities Catalog: CVE-2020-25183 is NOT listed (confirmed absent as of analysis date) — https://www.cisa.gov/known-exploited-vulnerabilities-catalog
5. EPSS (Exploit Prediction Scoring System): EPSS Score 0.00787, 52.8% percentile — https://www.first.org/epss/

Threat actor campaign evidence: No known threat actor campaigns or active exploitation in the wild have been publicly documented for CVE-2020-25183. The CISA KEV catalog does not include this CVE, and the EPSS percentile (52.8%) suggests moderate potential for exploitation but no confirmed in-the-wild activity. The vulnerability is primarily a concern for patient privacy and safety in proximity-based attack scenarios, given the IoT nature of the device and inherent Bluetooth range limitation.