CVE-2023-35386: Windows 10 1507 Privilege Escalation Flaw

CVE-2023-35386 Overview

CVE-2023-35386 is a Windows Kernel Elevation of Privilege vulnerability that allows an authenticated attacker with local access to escalate privileges on affected Windows systems. The vulnerability exists in the Windows kernel and can be exploited by a local attacker to gain elevated system privileges, potentially achieving SYSTEM-level access from a low-privileged user context.

Critical Impact

Successful exploitation allows attackers to escalate from low-privileged user accounts to SYSTEM-level access, enabling complete compromise of affected Windows systems including data theft, malware installation, and lateral movement across enterprise networks.

Affected Products

• Microsoft Windows 10 (versions 1507, 1607, 1809, 21H2, 22H2)
• Microsoft Windows 11 (versions 21H2, 22H2)
• Microsoft Windows Server 2012 R2
• Microsoft Windows Server 2016
• Microsoft Windows Server 2019
• Microsoft Windows Server 2022

Discovery Timeline

• August 8, 2023 - CVE-2023-35386 published to NVD
• January 1, 2025 - Last updated in NVD database

Technical Details for CVE-2023-35386

Vulnerability Analysis

This vulnerability is classified under CWE-125 (Out-of-Bounds Read), indicating a memory corruption flaw in the Windows kernel. The vulnerability involves an integer overflow condition that leads to an out-of-bounds read operation within kernel memory space. When triggered, an attacker who has already obtained local access to the system can exploit this flaw to read sensitive kernel memory contents or manipulate kernel data structures, ultimately achieving privilege escalation.

The local attack vector requires the attacker to first gain initial access to the target system through another means, such as phishing, exploiting a separate vulnerability, or using legitimate credentials. Once local access is established, the low attack complexity means that exploitation is relatively straightforward without requiring special conditions or additional user interaction.

Root Cause

The root cause of CVE-2023-35386 lies in improper bounds checking within Windows kernel code paths. An integer overflow condition occurs during arithmetic operations, which subsequently causes the kernel to perform memory read operations beyond the intended buffer boundaries. This out-of-bounds read can expose sensitive kernel memory data or enable manipulation of kernel structures that control privilege levels.

The vulnerability stems from insufficient validation of input parameters that influence memory allocation sizes or buffer offsets, allowing crafted input to trigger the integer overflow condition.

Attack Vector

The attack vector for CVE-2023-35386 is local, meaning an attacker must have authenticated access to the target system to exploit this vulnerability. The attack sequence typically involves:

1. Initial Access: The attacker first gains local access to a Windows system through legitimate credentials, social engineering, or exploitation of another vulnerability
2. Triggering the Vulnerability: The attacker executes a specially crafted application or uses system calls that trigger the integer overflow condition in the kernel
3. Memory Corruption: The integer overflow causes an out-of-bounds read operation in kernel memory
4. Privilege Escalation: By manipulating the corrupted memory state or leveraging the information disclosed, the attacker elevates privileges to SYSTEM level

Technical details and exploitation information are available in the Packet Storm Security advisory, which documents the integer overflow and out-of-bounds read mechanism. The vulnerability exploitation typically requires crafting specific input that causes arithmetic operations to overflow, resulting in incorrectly sized memory allocations or buffer operations that the attacker can leverage for privilege escalation.

Detection Methods for CVE-2023-35386

Indicators of Compromise

• Unusual process behavior with processes attempting to access kernel memory regions or make suspicious system calls associated with privilege escalation
• Unexpected SYSTEM-level processes spawned from low-privileged user sessions
• Anomalous kernel crash dumps or blue screen events that may indicate exploitation attempts
• Process hollowing or suspicious parent-child process relationships involving kernel-mode operations

Detection Strategies

• Deploy endpoint detection and response (EDR) solutions capable of monitoring kernel-level activities and detecting privilege escalation attempts
• Enable Windows Security Event logging for process creation events (Event ID 4688) with command-line auditing to track suspicious process executions
• Implement behavioral analysis to detect anomalous transitions from user-mode to kernel-mode privileges
• Monitor for processes attempting to exploit kernel vulnerabilities using YARA rules or signature-based detection

Monitoring Recommendations

• Configure SentinelOne agents to monitor for privilege escalation behavioral patterns and kernel exploitation techniques
• Enable Sysmon with appropriate configuration to log process access events and image loads related to kernel operations
• Implement network segmentation and monitor lateral movement attempts following potential privilege escalation
• Regularly review Windows Event Logs for security-related events indicating unauthorized privilege changes

How to Mitigate CVE-2023-35386

Immediate Actions Required

• Apply Microsoft security updates from the August 2023 Patch Tuesday release immediately on all affected Windows systems
• Prioritize patching for internet-facing systems and critical infrastructure servers
• Implement the principle of least privilege to minimize the impact of potential exploitation
• Conduct vulnerability scanning to identify all systems running affected Windows versions

Patch Information

Microsoft has released security updates to address CVE-2023-35386 as part of the August 2023 security updates. Detailed patch information and download links are available in the Microsoft Security Response Center advisory. Organizations should apply the appropriate cumulative update for their specific Windows version:

• Windows 10 and Windows 11 systems should receive updates through Windows Update or WSUS
• Windows Server systems should be patched through standard enterprise patch management processes
• Ensure systems are configured to receive and install security updates promptly

Workarounds

• Restrict local access to critical systems by implementing strong access controls and multi-factor authentication
• Limit administrative privileges and use separate accounts for administrative tasks
• Deploy application whitelisting solutions to prevent execution of unauthorized applications that could exploit this vulnerability
• Isolate high-value systems and implement network segmentation to contain potential compromise

# Verify patch installation status using PowerShell
Get-HotFix | Where-Object {$_.InstalledOn -gt "2023-08-01"} | Select-Object HotFixID, InstalledOn
# Check Windows Update history for August 2023 updates
Get-WindowsUpdateLog
# Verify current Windows build version
winver