Security Advisory 2110-01

Insecure data storage in Polar Flow Android application


Advisory ID: TRSA-2110-01
Advisory version: 1.0
Advisory status: Public
Advisory URL:
Affected product: Polar Flow Android mobile application (fi.polar.polarflow)
Affected version: 5.7.1
Vendor: Polar Electro,
Credits: Trovent Security GmbH, Karima Hebbal

Detailed description

The Polar Flow app is a sports, fitness and activity analyzer which allows to plan and monitor training, daily activity and sleep.
Trovent Security GmbH discovered that the application stores the username and password in clear text in a file on the mobile device.

Severity: Medium
CVSS Score: 4.4 (CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N)

Proof of concept

Content of the file /data/data/fi.polar.polarflow/shared_prefs/UserData3.xml:

<?xml version='1.0' encoding='utf-8' standalone='yes' ?>
    <string name="current_device_id">no_device</string>
    <int name="last_version_code" value="5070103" />
    <string name="base_url"></string>
    <string name="last_name">Ptest</string>
    <int name="key_initial_view_resource_id" value="2131363187" />
    <boolean name="valid_ver_two" value="true" />
    <long name="problem_phone_message_time" value="1634888249727" />
    <boolean name="new_blogs_available" value="true" />
    <string name="address_json">{&quot;city&quot;:&quot;\u003cscript\u003ealert(1)\u003c/script\
    <string name="profile_json">{&quot;favoriteSports&quot;:[]}</string>
    <string name="password">Test2021</string>
    <string name="last_blog_sync_time">2021-10-22T09:37:18.309</string>
    <long name="user_id" value="54871065" />
    <boolean name="initial_remote_sync_executed" value="true" />
    <string name="preferred_blog_language">en</string>
    <int name="key_training_diary_tab" value="0" />
    <string name="first_name">Ptest</string>
    <int name="should_show_problem_phone_message" value="2" />
    <string name="username"></string>

Solution / Workaround

We recommend not to store sensitive information in clear text on the mobile device.

Fixed in version 6.3.0, verified by Trovent.


2021-10-18: Vulnerability found
2021-12-15: Vendor contacted
2022-01-20: Contacted vendor again
2022-01-21: Vendor replied that the vulnerability will be checked
2022-01-28: Vendor replied, the vulnerability will be fixed in a future update
2022-07-27: Vendor contacted, asking for status
2022-08-09: Vendor replied, the vulnerability is fixed since version 6.3.0
2022-08-17: Trovent verified remediation of the vulnerability
2022-08-18: Advisory published