CVE-2024-40674 Overview
CVE-2024-40674 is a local denial-of-service vulnerability in the Android WiFi module. The flaw resides in the validateSsid method of WifiConfigurationUtil.java. A logic error in SSID validation allows a system configuration file to overflow, corrupting persisted WiFi state. The issue affects Google Android 14 and requires no user interaction or elevated privileges to exploit. Google addressed the flaw in the October 2024 Android Security Bulletin. The weakness is classified as [CWE-120] Buffer Copy without Checking Size of Input.
Critical Impact
Local applications can trigger a persistent denial-of-service condition on the WiFi subsystem without additional execution privileges or user interaction.
Affected Products
- Google Android 14
- Android Open Source Project (AOSP) WiFi module
- Devices running unpatched builds prior to the October 2024 security patch level
Discovery Timeline
- 2024-10-01 - Google publishes fix in the Android Security Bulletin
- 2025-01-28 - CVE-2024-40674 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2024-40674
Vulnerability Analysis
The vulnerability exists in the validateSsid function inside WifiConfigurationUtil.java, part of the Android WiFi module. The function validates Service Set Identifier (SSID) strings supplied during WiFi network configuration. A logic error in the length checks permits input that exceeds the intended bounds when persisted to a system configuration file. Repeated or malformed submissions cause the underlying storage file to grow beyond expected limits, degrading or disabling WiFi configuration handling.
The outcome is a local denial-of-service condition against the WiFi service. Confidentiality and integrity of user data are not directly affected. Exploitation requires no user interaction and no additional privileges beyond what a locally installed app can request.
Root Cause
The root cause is improper input validation in the SSID length-checking logic. The validator fails to enforce the correct upper bound before values are written to the WiFi configuration store. This allows oversized or crafted SSID entries to accumulate in the configuration file. Over time, this overflows the file and disrupts normal WiFi subsystem behavior.
Attack Vector
A local attacker with the ability to invoke WiFi configuration APIs can supply crafted SSID values that bypass the length check. Repeated submissions grow the configuration file until the WiFi service can no longer process it correctly. The result is a denial of service against WiFi configuration and connectivity on the device.
No verified public proof-of-concept code is available. Technical details of the fix are visible in the Android WiFi Module Commit.
Detection Methods for CVE-2024-40674
Indicators of Compromise
- Abnormal growth of the WiFi configuration file on the device (WifiConfigStore.xml and related stores)
- WiFi service crashes, restarts, or persistent failures to save network configurations
- Applications repeatedly invoking WifiManager.addNetwork or WifiManager.save with malformed SSID values
Detection Strategies
- Monitor mobile device fleets for the October 2024 or later Android security patch level via mobile device management (MDM) posture checks
- Inspect application permissions to identify apps holding CHANGE_WIFI_STATE that submit unusual network configurations
- Correlate WiFi service crash logs (logcat entries from WifiService) with recent app installations or updates
Monitoring Recommendations
- Track Android Security Bulletin patch level reporting across managed Android 14 devices
- Enable mobile threat defense telemetry for anomalous WiFi API usage patterns
- Review app behavior for repeated failed WiFi configuration attempts that may indicate exploitation
How to Mitigate CVE-2024-40674
Immediate Actions Required
- Apply the October 2024 Android security patch level or later on all Android 14 devices
- Enforce a minimum patch level through MDM policies and block enrollment of devices below that baseline
- Audit installed applications for unnecessary WiFi configuration permissions and remove untrusted apps
Patch Information
Google released the fix in the Android Security Bulletin October 2024. The corresponding AOSP change is available in the Android WiFi Module Commit. Device manufacturers integrate the patch into their monthly OEM security updates. Users should install the latest available system update from their vendor.
Workarounds
- Restrict installation of apps requesting CHANGE_WIFI_STATE unless business-justified
- Use enterprise mobility controls to limit WiFi configuration changes to managed profiles
- If patching is delayed, reset WiFi settings to clear an oversized configuration file and restore normal operation
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
