Varied Functionality of MonitorMinor App Outstrips All Other Mobile Stalkerware

March 17, 2020 @ 1:40 PM
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2 min read

Security researchers observed that the MonitorMinor app outstrips the capabilities of all other mobile stalkerware strains detected thus far.

Kaspersky Lab found that this stalkerware app, detected as Monitor.AndroidOS.MonitorMinor.c, is capable of running the SuperUser (SU) utility on an infected Android device. When it did, the app granted itself root-level privileges and thereby gained access to numerous social networking apps and messengers, such as Gmail, Instagram, Facebook, Skype and Snapchat.

But MonitorMinor didn’t stop there. The app also leveraged its SU rights to steal the data/system/gesture.key, a file that contains the hash sum for the screen unlock code and credentials. Those operating the app could have then abused that data to unlock the infected device when it was nearby or when they acquired physical access to it — a first for Kaspersky in all its years of monitoring mobile threats.

Even when it didn’t run the SU utility, MonitorMinor retained the ability to effectively operate on most Android devices and intercept events from installed apps by abusing Accessibility Services.

A Look Back at Other Mobile Stalkerware

MonitorMinor is not the only stalkerware app that security researchers have detected over the past year. Back in August 2019, for instance, ESET discovered Android/Spy.Agent.AOX, spyware that attackers created using the AhMyth open-source espionage tool. It had infiltrated the Google Play store on at least two separate occasions at the time of discovery.

Just a few months later in December 2019, Juniper took a deep dive into FlexiSPY and found that the app was capable of exfiltrating data from a victim’s Gmail account, tracking a victim’s GPS location and recording browsing activity, among other features. In February 2020, TechCrunch reported on KidsGuard, an app that could “monitor everything” and “access all the information” on a target device.

How to Defend Against Stalkerware

Stalkerware programs such as MonitorMinor pose a serious threat to both users and organizations alike. These malicious apps provide attackers with a way to learn more about their victim and possibly even intercept messages like 2-Step Verification codes, all for the purpose of perpetrating identity theft. Along those same lines, these programs can lay the groundwork for mobile attackers to bypass identity and access management (IAM) solutions and access sensitive corporate information that’s accessible via mobile apps.

Acknowledging these threats, security professionals can help their organizations stay safe by deploying a unified endpoint management (UEM) solution to monitor mobile apps for suspicious activity, such as running the SU utility. Companies should also implement ongoing security awareness training to educate employees about mobile security best practices, which include using a password management app and regularly changing lock screen credentials.

David Bisson
Contributing Editor

David Bisson is an infosec news junkie and security journalist. He works as Contributing Editor for Graham Cluley Security News and Associate Editor for Trip...
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