Temp / Cache File Leftovers

← Insecure Data Storage

temp_file_leftovers   MEDIUM

Description

Decrypted/sensitive content written to temp/cache dirs and never cleaned up.

How it works

An export/decrypt flow writes the decrypted, sensitive content to a predictable temp file in cleartext and never deletes it. This writes a file into the app temp/cache directory on-device; the leftover survives after use and is recoverable via adb or a rooted/jailbroken device, a file browser, or forensic tooling.

How to exercise it. DVMA is the harness - open this module from the home index and tap the demo action. The screen ships the malicious input and simulates the attacker (e.g. the companion app, crafted intent, or scanned payload) in-process, and the evidence panel prints the proof. The Tools (optional) and Attack inputs below are only needed to reproduce the exploit end-to-end on a real device.

Exploit steps

1. Set up. Build DVMA with a flavor that enables the Insecure Data Storage category (e.g. --dart-define-from-file=config/flavors/dev.json) and run on an emulator/simulator you control. The demo needs no external tooling; for the optional on-device reproduction the relevant tools are: objection · Android: adb, run-as · iOS: ifuse, afcclient.
2. Locate the target. From the home index, open Temp / Cache File Leftovers (temp_file_leftovers). The How it works section above describes this module’s specific weakness; the screen states the intended-secure behavior and exposes the vulnerable action.
3. Exploit. Exercise the flow that persists data, then inspect on-device storage (adb shell run-as <pkg> / pull the app sandbox, or objection’s android keystore/ios nsuserdefaults helpers) and confirm the sensitive value is present in cleartext or without hardware backing.
4. Observe the evidence. Trigger the vulnerable action and read the evidence panel - it prints the concrete proof (leaked value, accepted replay, executed payload, or unauthorized result).
5. Contrast with the secure path. Run the module’s secure/hardened action (where provided) and confirm the same attack is rejected - this is what a correct implementation should do.
6. Map it back. Cross-reference the MASTG v2 test(s) MASTG-TEST-0207, MASTG-TEST-0299, MASTG-TEST-0302 for the canonical procedure and remediation.

Tools (optional)

• objection

Android

• adb
• run-as

iOS

• ifuse
• afcclient