CVE-2019-6741 – This vulnerability allows remote attackers to e... (How to Fix)

Q: What is the severity of CVE-2019-6741?

CVE-2019-6741 has a CVSS score of 9.3 (CRITICAL). This vulnerability allows remote attackers to execute arbitrary code on Samsung Galaxy S9 devices by exploiting a captive portal redirection flaw. Attackers can manipulate HTML to force page redirection and execute code in the context of the current process. Only Samsung Galaxy S9 devices prior to the January 2019 security update are affected.

📋 TL;DR

This vulnerability allows remote attackers to execute arbitrary code on Samsung Galaxy S9 devices by exploiting a captive portal redirection flaw. Attackers can manipulate HTML to force page redirection and execute code in the context of the current process. Only Samsung Galaxy S9 devices prior to the January 2019 security update are affected.

💻 Affected Systems

Products:

Samsung Galaxy S9

Versions: All versions prior to January 2019 Security Update (SMR-JAN-2019)

Operating Systems: Android

Default Config Vulnerable: ⚠️ Yes

Notes: Requires user to connect to a malicious wireless network with captive portal.

📦 What is this software?

Galaxy S9 Firmware by Samsung

View all CVEs affecting Galaxy S9 Firmware →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Full device compromise allowing remote code execution, data theft, and persistent backdoor installation.

🟠

Likely Case

Limited code execution within captive portal context, potentially leading to credential theft or further exploitation.

🟢

If Mitigated

No impact if patched or if device doesn't connect to malicious captive portals.

🌐 Internet-Facing: HIGH - Exploitation requires connecting to attacker-controlled wireless networks which can be set up in public spaces.

🏢 Internal Only: LOW - Requires physical proximity or internal network compromise to set up malicious captive portal.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: LIKELY

Unauthenticated Exploit: ⚠️ Yes

Complexity: MEDIUM

Exploitation requires HTML manipulation and user connecting to malicious network. ZDI-CAN-7476 identifier suggests detailed research exists.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: January 2019 Security Update (SMR-JAN-2019 - SVE-2018-13467)

Vendor Advisory: https://security.samsungmobile.com/securityUpdate.smsb

Restart Required: Yes

Instructions:

1. Go to Settings > Software update > Download and install. 2. Apply January 2019 security update. 3. Restart device after installation.

🔧 Temporary Workarounds

Avoid untrusted Wi-Fi networks

all

Prevent connection to potentially malicious captive portals

Disable automatic Wi-Fi connections

all

Prevent automatic connection to open or remembered networks

🧯 If You Can't Patch

Use VPN when connecting to any public or untrusted Wi-Fi network
Disable captive portal detection in developer options (not recommended for general use)

🔍 How to Verify

Check if Vulnerable:

Check Settings > About phone > Software information > Android security patch level. If before January 2019, device is vulnerable.

Check Version:

Not applicable - check via device settings UI

Verify Fix Applied:

Verify Android security patch level shows 'January 1, 2019' or later.

📡 Detection & Monitoring

Log Indicators:

Unusual captive portal redirects
Suspicious HTML/JavaScript execution in browser logs

Network Indicators:

Connection to unknown captive portals
Unusual HTTP redirect patterns

SIEM Query:

Not applicable for mobile device detection

📊 Metadata

CVE ID: CVE-2019-6741

CVSS v3 Score: 9.3 (CRITICAL)

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N

CWE: CWE-601

Published: June 3, 2019

Last Updated: November 21, 2024

🔗 References

https://www.zerodayinitiative.com/advisories/ZDI-19-254/ Third Party Advisory,VDB Entry
https://www.zerodayinitiative.com/advisories/ZDI-19-254/ Third Party Advisory,VDB Entry

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🔗 Related Vulnerabilities

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