CVE-2023-32402: Apple Safari Information Disclosure Flaw

CVE-2023-32402 Overview

CVE-2023-32402 is an out-of-bounds read vulnerability affecting Apple's WebKit rendering engine and multiple Apple operating systems. The vulnerability stems from insufficient input validation when processing web content, allowing attackers to potentially disclose sensitive information from device memory. This issue was addressed by Apple with improved input validation in security updates released in May 2023.

Critical Impact

Processing maliciously crafted web content may allow an attacker to read beyond allocated memory boundaries, potentially exposing sensitive information stored in device memory including credentials, session tokens, or private data.

Affected Products

• Apple Safari versions prior to 16.5
• Apple iOS versions prior to 16.5 and iPadOS versions prior to 16.5
• Apple macOS Ventura versions prior to 13.4
• Apple tvOS versions prior to 16.5
• Apple watchOS versions prior to 9.5

Discovery Timeline

• June 23, 2023 - CVE-2023-32402 published to NVD
• November 21, 2024 - Last updated in NVD database

Technical Details for CVE-2023-32402

Vulnerability Analysis

This vulnerability is classified as CWE-125 (Out-of-Bounds Read), a memory safety issue that occurs when software reads data from a location that is outside the intended buffer boundaries. In the context of WebKit, which processes complex web content including HTML, CSS, JavaScript, and media files, improper bounds checking during input processing creates the opportunity for memory disclosure.

The attack requires user interaction, as the victim must visit a malicious website or process attacker-controlled web content through an affected application. Upon successful exploitation, the attacker gains read access to memory regions outside the intended buffer, potentially extracting sensitive information such as cryptographic keys, authentication tokens, or other private data resident in memory.

The vulnerability affects the core rendering engine shared across multiple Apple platforms, explaining the wide range of affected products from mobile devices (iPhone, iPad) to desktop (macOS) and wearable/entertainment devices (watchOS, tvOS).

Root Cause

The root cause of CVE-2023-32402 lies in insufficient input validation within WebKit's content processing routines. When handling certain types of web content, the rendering engine failed to properly validate array indices or buffer boundaries before performing read operations. This allowed crafted input to trigger memory reads beyond the allocated buffer space, exposing adjacent memory contents to the attacker.

Attack Vector

The attack vector for this vulnerability is network-based and requires user interaction. An attacker would need to:

1. Craft a malicious web page containing specially designed content that triggers the out-of-bounds read
2. Lure the victim to visit the malicious page using Safari or an application that uses WebKit for rendering
3. The vulnerable WebKit engine processes the malicious content without proper bounds validation
4. Memory contents beyond the intended buffer are read and can potentially be exfiltrated to the attacker

This attack could be delivered through phishing emails, malicious advertisements, or compromised legitimate websites. The information disclosed could include sensitive data from other web sessions, cached credentials, or system information.

Detection Methods for CVE-2023-32402

Indicators of Compromise

• Unusual memory access patterns or crashes in Safari or WebKit-based applications
• Browser processes attempting to access memory regions outside normal operational boundaries
• Unexpected network traffic from browser processes potentially exfiltrating read memory data
• System logs indicating WebKit crashes or abnormal termination during web browsing

Detection Strategies

• Monitor for WebKit process crashes or abnormal behavior that may indicate exploitation attempts
• Implement network monitoring to detect suspicious outbound connections from browser processes
• Deploy endpoint detection solutions that can identify memory access violations in WebKit components
• Review application crash reports for patterns consistent with out-of-bounds memory access

Monitoring Recommendations

• Enable crash reporting and logging for Safari and WebKit-based applications
• Monitor system integrity logs for signs of memory corruption or disclosure
• Implement browser isolation technologies to contain potential exploitation
• Use network traffic analysis to identify potential data exfiltration attempts from browser processes

How to Mitigate CVE-2023-32402

Immediate Actions Required

• Update all Apple devices to the patched versions: iOS/iPadOS 16.5, macOS Ventura 13.4, Safari 16.5, tvOS 16.5, and watchOS 9.5
• Enable automatic updates on all Apple devices to ensure timely security patch deployment
• Audit organization assets to identify all devices running vulnerable Apple software versions
• Consider implementing web content filtering to block access to known malicious sites until patching is complete

Patch Information

Apple has released security updates addressing this vulnerability across all affected platforms. Organizations and users should apply the following updates immediately:

• Safari 16.5 - See Apple Security Update Guide
• iOS 16.5 and iPadOS 16.5 - See Apple Security Update Information
• macOS Ventura 13.4 - See Apple Security Fix Details
• tvOS 16.5 - See Apple Security Advisory
• watchOS 9.5 - See Apple Vulnerability Disclosure

Workarounds

• Limit web browsing to trusted sites until patches can be applied
• Use alternative browsers that do not rely on WebKit rendering engine where possible
• Implement network-level web filtering to block potentially malicious content
• Enable enhanced security features such as Lockdown Mode on iOS devices for high-risk users

# Check current macOS version for patch verification
sw_vers -productVersion
# Expected output for patched systems: 13.4 or higher

# Check iOS/iPadOS version via command line (using Apple Configurator or MDM)
# Navigate to Settings > General > About to verify version 16.5 or higher

# For enterprise environments, use MDM to query device versions
# and enforce compliance with minimum version requirements