Polar Flow Android 5.7.1 Secret Disclosure Vulnerability

Insecure data storage in Polar Flow Android application
#######################################################


Overview
########

Advisory ID: TRSA-2110-01
Advisory version: 1.0
Advisory status: Public
Advisory URL: https://trovent.io/security-advisory-2110-01
Affected product: Polar Flow Android mobile application (fi.polar.polarflow)
Affected version: 5.7.1
Vendor: Polar Electro, https://flow.polar.com
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)
CVE ID: N/A
CWE ID: CWE-312


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' ?>
<map>
    <string name="current_device_id">no_device</string>
    <int name="last_version_code" value="5070103" />
    <string name="base_url">https://www.polarremote.com/v2/users/54871065</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">{"city":"\u003cscript\u003ealert(1)\u003c/script\
u003e","countryCode":"DE","modified":"2021-10-22T07:37:5
3.000Z"}</string>
    <string name="profile_json">{"favoriteSports":[]}</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">[email protected]</string>
</map>

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


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.