Description
A critical vulnerability has been identified in the Windows Lightweight Directory Access Protocol (LDAP). This vulnerability allows for remote code execution, meaning an attacker can potentially gain control over an affected system.
Affected Product(s)
- Windows 10 Version 1607 for 32-bit Systems (versionEndExcluding: 10.0.14393.7606),
- Windows 10 Version 1607 for x64-based Systems (versionEndExcluding: 10.0.14393.7606)
Technical Details
The vulnerability exists in the Lightweight Directory Access Protocol (LDAP) implementation on Windows 10 Version 1607 systems. LDAP is an open, vendor-neutral, industry-standard application protocol for accessing and maintaining distributed directory information services over an Internet Protocol (IP) network.
Active Directory uses this protocol within Windows environments to access and manage directories. The identified flaw is serious, given the CVSSv3 score of 9.8, categorized as ‘critical.’ This high severity highlights the ease with which the vulnerability can be exploited, as well as its potential impact. Specifically, the issue is related to a remote code execution (RCE) vulnerability that threat actors could leverage to execute arbitrary code on the compromised system.
Remote code execution vulnerabilities pose a high risk to affected systems because they allow an attacker to run malicious code on the target machine, potentially leading to a complete takeover. In the worst-case scenario, an attacker could install programs; view, change, or delete data; or create new accounts with full user rights.
The vulnerability is linked to a flaw in the parsing functionality of Windows LDAP. Exploitation typically involves carefully crafted LDAP requests that trigger this vulnerability, resulting in the execution of arbitrary code. The inherent nature of directory services in enterprise environments—the very areas where LDAP is heavily used—increases the potential impact, as these environments often contain critical assets and sensitive information.
Versions prior to 10.0.14393.7606 of Windows 10 Version 1607 for both 32-bit and x64 systems are specifically vulnerable. After this version, the issue has been addressed by the vendor. Microsoft has released several critical updates that resolve this issue. The following software configurations are vulnerable:
- Windows 10 Version 1607 for 32-bit Systems (versionEndExcluding: 10.0.14393.7606)
- Windows 10 Version 1607 for x64-based Systems (versionEndExcluding: 10.0.14393.7606) Security patches addressing this issue have been included in KB5048671, KB5048661, KB5048652, KB5048703, KB5048654, KB5048685, KB5048699, KB5048735, KB5048695, and KB5048710 updates provided by Microsoft.
It’s important to note the role of the Common Weakness Enumeration (CWE) identifier in understanding the technical aspects of vulnerabilities. In this case, the weakness is categorized under CWE-190 (Integer Overflow or Wraparound). This classification indicates that the vulnerability arises from the software’s insufficient handling of integer values, which can lead to unexpected behavior when the integer exceeds the storage limit or wraps around. The problem often becomes a gateway for arbitrary code execution when exploited by threat actors.
To address these issues, Microsoft has advised users to apply the updates mentioned in the security patches. Each patch corrects the underlying integer overflow, ensuring the LDAP parser functions safely even when handling malformed input designed to exploit this weakness. The critical severity also points to the need for immediate action by users and administrators. Delaying updates could leave systems vulnerable to exploitation.
Therefore, thorough patch management practices, including prioritization of these specific updates, are quintessential for maintaining optimum security postures in environments that rely on the affected software.
Weakness
This vulnerability is associated with the weakness classified under CWE-190, known as “Integer Overflow or Wraparound.” This type of weakness occurs when an arithmetic operation reaches the limit of the integer value type, leading to unexpected behavior or overwriting data crucial to the program’s control flow.
Impact Assessment
If exploited, this vulnerability could allow an attacker to gain unauthorized control over the system by executing arbitrary code. This could lead to the installation of malicious programs, alteration or deletion of data, or creation of new user accounts with full privileges, effectively compromising the integrity, availability, and confidentiality of the information maintained by the system.
Active Exploitation
We have observed activity from known adversary groups exploiting similar vulnerabilities in the past, especially those groups targeting remote code execution vulnerabilities in network services provided by popular operating systems.
Ransomware Association
The vulnerability has been linked to ransomware attacks, specifically those that exploit directory service flaws to gain initial access to the system. These types of attacks leverage the compromised system as an entry point to deploy ransomware, locking users out of their data until a ransom is paid.
Mitigation and Resolution
We have released a patch that addresses this vulnerability. Please update to version 10.0.14393.7606 immediately to protect your systems from potential exploitation.
Recommendations
- We strongly recommend that all customers apply the latest patch as soon as possible.
- Verify installation of the patches by checking the file version of ntoskrnl.exe as guided.
- Refer to KB5048671, KB5048661, KB5048652, KB5048703, KB5048654, KB5048685, KB5048699, KB5048735, KB5048695, and KB5048710 updates for security patch details.
- Continually monitor systems and networks for unusual activities and potential indicators of compromise (IoCs).
- Conduct a risk assessment to determine the criticality of the affected systems and prioritize patch deployment accordingly.
- Ensure backup and recovery strategies are up-to-date and tested to minimize impact should a ransomware attack occur.
- Implement network segmentation and least privilege principles to limit the spread of attacks within your environments.
References