CVE-2025-24169: Apple Safari Auth Bypass Vulnerability

CVE-2025-24169 Overview

A logging issue in Apple Safari and macOS has been identified that allows a malicious application to bypass browser extension authentication. The vulnerability stems from improper data redaction in logging mechanisms, potentially exposing sensitive authentication data that could be leveraged by attackers to compromise browser extension security controls.

Critical Impact

A malicious app may be able to bypass browser extension authentication, potentially allowing unauthorized access to extension functionality and sensitive user data.

Affected Products

• Apple Safari (versions prior to 18.3)
• Apple macOS (versions prior to Sequoia 15.3)

Discovery Timeline

• 2025-01-27 - CVE-2025-24169 published to NVD
• 2025-11-03 - Last updated in NVD database

Technical Details for CVE-2025-24169

Vulnerability Analysis

This vulnerability is classified under CWE-532 (Insertion of Sensitive Information into Log File), indicating that the affected software writes sensitive data to log files in an insecure manner. The logging implementation in Safari and macOS failed to properly redact authentication-related information used by browser extensions, creating an information disclosure vector that malicious applications could exploit.

The attack can be initiated remotely without requiring any user interaction or prior authentication. When exploited, the vulnerability impacts the integrity of the authentication system, allowing attackers to bypass security controls designed to protect browser extensions. While confidentiality is not directly impacted according to the CVSS metrics, the integrity compromise is significant as it undermines the trust model between the browser and its extensions.

Root Cause

The root cause of this vulnerability lies in insufficient data redaction within the logging subsystem. When browser extension authentication events occur, the system logs certain authentication parameters or tokens without proper sanitization. A malicious application with access to these log files can extract this information and use it to impersonate legitimate authentication flows, effectively bypassing extension authentication mechanisms.

Attack Vector

The vulnerability is exploitable over the network with low attack complexity. An attacker would need to deploy a malicious application on the target system that can access the improperly redacted log files. Once the authentication data is harvested from the logs, the malicious application can forge or replay authentication requests to gain unauthorized access to browser extension functionality.

The attack flow involves:

1. A malicious application gains execution on the target macOS system
2. The application monitors or accesses system log files containing Safari extension authentication data
3. Authentication tokens or credentials are extracted from the improperly redacted log entries
4. The malicious application uses this data to bypass browser extension authentication
5. The attacker gains unauthorized control over extension capabilities

Detection Methods for CVE-2025-24169

Indicators of Compromise

• Unusual applications accessing Safari or macOS system log files
• Unexpected browser extension behavior or unauthorized extension installations
• Log file access patterns from non-standard processes
• Authentication anomalies in browser extension communication

Detection Strategies

• Monitor for suspicious processes accessing system log directories containing Safari-related logs
• Implement endpoint detection rules for applications attempting to read browser authentication artifacts
• Review installed applications for unknown or untrusted software that may be harvesting log data
• Configure SentinelOne Singularity to detect and alert on anomalous log file access patterns

Monitoring Recommendations

• Enable enhanced logging for application access to sensitive system directories
• Deploy behavioral analysis to detect applications exhibiting data harvesting behaviors
• Implement file integrity monitoring on directories containing browser authentication logs
• Configure alerts for any non-Apple processes accessing Safari extension authentication pathways

How to Mitigate CVE-2025-24169

Immediate Actions Required

• Update macOS to version Sequoia 15.3 or later immediately
• Update Safari to version 18.3 or later on all affected systems
• Audit installed applications and remove any suspicious or untrusted software
• Review browser extension permissions and revoke access for any unauthorized extensions

Patch Information

Apple has released security updates to address this vulnerability with improved data redaction in the logging subsystem. The patches are available in:

• macOS Sequoia 15.3 - See Apple Support Document #122074 for details
• Safari 18.3 - See Apple Support Document #122068 for details

Organizations should prioritize applying these updates across all affected macOS systems and ensure Safari is updated to the patched version.

Workarounds

• Restrict application installation to only trusted sources (Mac App Store and identified developers)
• Limit browser extension installations to essential, verified extensions only
• Enable System Integrity Protection (SIP) to prevent unauthorized access to protected system areas
• Consider implementing application allowlisting to prevent execution of untrusted applications

# Verify macOS and Safari versions
sw_vers -productVersion
/Applications/Safari.app/Contents/MacOS/Safari --version

# Check System Integrity Protection status
csrutil status

# List installed browser extensions for audit
defaults read ~/Library/Safari/Extensions