t1661-application-versioning

name	T1661_application-versioning
description	An adversary may push an update to a previously benign application to add malicious code.
category	input-validation
version	18.1
author	cyberstrike-official
tags	["mitre-attack","mobile","t1661","initial-access","defense-evasion","android","ios"]
technique_id	T1661
tactic	initial-access
all_tactics	["initial-access","defense-evasion"]
platforms	["Android","iOS"]
mitre_url	https://attack.mitre.org/techniques/T1661
tech_stack	["android","ios"]
cwe_ids	["CWE-20"]
chains_with	[]
prerequisites	[]
severity_boost	{}

T1661 Application Versioning

High-Level Description

An adversary may push an update to a previously benign application to add malicious code. This can be accomplished by pushing an initially benign, functional application to a trusted application store, such as the Google Play Store or the Apple App Store. This allows the adversary to establish a trusted userbase that may grant permissions to the application prior to the introduction of malicious code. Then, an application update could be pushed to introduce malicious code.

This technique could also be accomplished by compromising a developer’s account. This would allow an adversary to take advantage of an existing userbase without having to establish the userbase themselves.

Kill Chain Phase

• Initial Access (TA0027)
• Defense Evasion (TA0030)

Platforms: Android, iOS

What to Check

• Identify if Application Versioning technique is applicable to target mobile environment
• Check Android devices for indicators of Application Versioning
• Check iOS devices for indicators of Application Versioning
• Verify mitigations are bypassed or absent (2 known mitigations)
• Assess detection coverage (1 detection strategies)

How to Test

Identify Attack Surface

Determine if the target mobile environment is susceptible to Application Versioning by examining the target platforms (Android, iOS).

Assess Existing Defenses

Review whether mitigations for T1661 are in place. If defenses are absent or misconfigured, this technique may be exploitable.

Remediation Guide

M1012 Enterprise Policy

Enterprises can provision policies to mobile devices for application allow-listing, ensuring only approved applications are installed onto mobile devices.

M1006 Use Recent OS Version

Android 11 and above implement application hibernation, which can hibernate an application that has not been used for a few months and can reset the application’s permission requests.

Detection

Detection of Application Versioning

Risk Assessment

Finding	Severity	Impact
Application Versioning technique applicable	Low