CVE-2021-41096
📋 TL;DR
Rucky versions 2.2 and earlier (release builds) and 425 and earlier (nightly builds) use weak RSA/ECB/PKCS1Padding encryption, which could allow attackers to decrypt sensitive data. This affects Android users running vulnerable Rucky versions for USB HID Rubber Ducky functionality. The vulnerability stems from using outdated cryptographic algorithms that are susceptible to attacks.
💻 Affected Systems
- Rucky
📦 What is this software?
Rucky by Rucky Project
⚠️ Risk & Real-World Impact
Worst Case
Attackers could decrypt sensitive data transmitted or stored by Rucky, potentially exposing credentials, configuration data, or other protected information.
Likely Case
Information disclosure of encrypted data if attackers can intercept or access encrypted communications or storage.
If Mitigated
Minimal impact if strong encryption is implemented or if the vulnerable feature is disabled.
🎯 Exploit Status
Exploitation requires access to encrypted data and cryptographic analysis capabilities, but no public exploit code has been identified.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Release builds v2.3+, Nightly builds 426+
Vendor Advisory: https://github.com/mayankmetha/Rucky/security/advisories/GHSA-32m7-456v-wgfw
Restart Required: Yes
Instructions:
1. Update Rucky from Google Play Store or GitHub releases. 2. For nightly builds, update to version 426 or later. 3. Restart the application after update.
🔧 Temporary Workarounds
Disable Advanced Security Feature
androidIf the vulnerable encryption feature is not required, disable it in Rucky settings to mitigate the risk.
Open Rucky → Settings → Security → Disable 'Advanced Security' or similar encryption feature
🧯 If You Can't Patch
- Disable the advanced security feature in Rucky settings if not required
- Isolate Android devices running vulnerable Rucky versions from sensitive networks
🔍 How to Verify
Check if Vulnerable:
Check Rucky version in app settings: Open Rucky → Settings → About → Version numberCheck Version:
Not applicable via command line; check within Rucky app settingsVerify Fix Applied:
Confirm version is ≥2.3 for release builds or ≥426 for nightly builds, and verify encryption settings use stronger algorithms if available.📡 Detection & Monitoring
Log Indicators:
- Unusual cryptographic errors or warnings in Rucky logs
- Failed encryption/decryption attempts
Network Indicators:
- Not applicable - primarily local application
SIEM Query:
Not applicable for typical SIEM monitoring as Rucky operates locally on Android devices🔗 References
- https://github.com/mayankmetha/Rucky/commit/5e3a477365009f488a73efd26a91168502de1b93
- https://github.com/mayankmetha/Rucky/security/advisories/GHSA-32m7-456v-wgfw
- https://github.com/mayankmetha/Rucky/commit/5e3a477365009f488a73efd26a91168502de1b93
- https://github.com/mayankmetha/Rucky/security/advisories/GHSA-32m7-456v-wgfw
