CVE-2021-38646 is a high-severity vulnerability in Microsoft Office, specifically affecting the Access Connectivity Engine. This vulnerability allows attackers to execute remote code with local access, which could lead to unauthorized actions or data breaches. The CVSS score of 7.8 indicates the potential severity of this flaw, emphasizing the need for immediate attention from security teams. Organizations utilizing affected Microsoft Office versions need to prioritize patching to prevent exploitation.
The vulnerability was published on September 15, 2021, and has since undergone analysis. Security professionals should be aware that this vulnerability has a known exploitability status, making it critical to implement available patches as soon as possible. Organizations should assess their environments to identify any instances of the affected products to mitigate risks associated with this vulnerability.
The urgency for defenders can be classified as critical, necessitating immediate action to patch the vulnerability. This vulnerability poses a significant risk as it can lead to severe impacts on confidentiality, integrity, and availability of data within affected systems.
Organizations should implement a strategy to monitor for any unauthorized access attempts and ensure all relevant personnel are informed about the importance of applying security updates.
Vulnerability Details
CVE-2021-38646 is characterized as a remote code execution vulnerability within the Microsoft Office Access Connectivity Engine, which could allow an attacker to execute arbitrary code on the affected system. The vulnerability specifically affects several versions of Microsoft Office, including Office 2013, Office 2016, Office 2019, and Microsoft 365 Apps. The vulnerability was disclosed on September 15, 2021, and it is classified under the CVSS 3.1 with a base score of 7.8, indicating high severity.
The vulnerability has a local attack vector, low attack complexity, and does not require any privileges to exploit, but does require user interaction. The potential impacts include high confidentiality, integrity, and availability impacts, which can lead to significant data loss or system compromise.
Technical Analysis
The root cause of CVE-2021-38646 stems from the improper handling of user input by the Access Connectivity Engine, which can be exploited through malicious actions performed by a user with local access to the system. The attack vector is local, meaning that an attacker must have physical or remote access to the system. The attack complexity is low, allowing exploitation with minimal effort. Privileges required are none, indicating that any user can potentially trigger the vulnerability.
User interaction is required, as the attacker must convince the user to perform an action that triggers the vulnerability. The impact on confidentiality, integrity, and availability is high, making it crucial for organizations to address this vulnerability immediately.
Risk & Impact Analysis
Risk to organizations includes the potential for unauthorized access to sensitive information, loss of data integrity, and disruption of services. The blast radius for this vulnerability can be significant, especially in environments where multiple users have access to the affected software.
Given the high CVSS score and the known exploitation status, organizations should address this vulnerability in their priority patch cycle. The urgency is further underscored by its presence in the KEV (Known Exploited Vulnerabilities) catalog, indicating that it is actively being targeted by threat actors.
Signal | Status |
|---|---|
Known Exploit | Yes |
Public PoC | No |
Actively Exploited | Yes |
Ransomware Use | Yes |
Affected Versions
The vulnerable versions of Microsoft Office include: 365 Apps, Office 2013 SP1, Office 2016, and Office 2019. All versions prior to vendor patch are vulnerable.
Mitigation & Remediation
Organizations should apply the latest patches provided by Microsoft to mitigate this vulnerability. Specific patches for affected versions can be found in Microsoft's Security Update Guide. In case an immediate patch is not available, organizations should implement network controls and monitor systems for any unusual activity. Regular security assessments and configuration hardening can also help reduce the risk.
For further information on penetration testing services that can help validate your security posture, consider reviewing our offerings. Organizations should validate remediation effectiveness through penetration testing to identify similar weaknesses.
Detection Guidance
Monitoring user activity logs for any unauthorized access attempts is crucial. Organizations should also look for behavioral anomalies that deviate from normal user behavior, which may indicate exploitation of this vulnerability. Network signatures that can detect malicious payloads or commands executed via this vulnerability should be established.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2021-38646 lies in its potential for exploitation in environments where Microsoft Office is deployed. This vulnerability represents a common pattern seen in many software vulnerabilities, where user interaction plays a role in triggering exploits. Security teams should take proactive measures to educate users about the risks associated with executing files from untrusted sources.
Organizations can learn from this vulnerability's exploitation trends, highlighting the need for robust security training programs. Regularly updating software and implementing strict access controls will further strengthen defenses against similar vulnerabilities.
For additional resources on vulnerability management and best practices, consider reviewing our comprehensive guides on vulnerability management programs and the importance of penetration testing methodologies to ensure your organization is prepared.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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