Introduction
In November 2024, the Cybersecurity and Infrastructure Security Agency (CISA), in collaboration with international partners, released a comprehensive advisory detailing the top 15 vulnerabilities most frequently exploited by malicious actors in 2023. Understanding these vulnerabilities is crucial for organizations aiming to bolster their cybersecurity defenses. This article delves into each vulnerability, providing insights into their nature, impact, and recommended mitigation strategies.
Cyber threats continue to evolve, with attackers exploiting known vulnerabilities to infiltrate systems and compromise data. The 2023 advisory from CISA highlights the most targeted vulnerabilities, emphasizing the need for organizations to prioritize patching and implement robust security measures.
The Top 15 Exploited Vulnerabilities of 2023
Below is a detailed examination of each vulnerability, including its description, impact, and mitigation recommendations.
1. CVE-2023-23397: Microsoft Outlook Privilege Escalation Vulnerability
Description:
This vulnerability allows attackers to send a specially crafted email that triggers automatically when retrieved and processed by the Outlook client, leading to privilege escalation.
Impact:
Exploitation can result in unauthorized access to user credentials and potential lateral movement within the network.
Mitigation:
Apply the security update provided by Microsoft. Additionally, block TCP 445/SMB outbound traffic to the internet from the network.
Reference:
Microsoft Security Update Guide
2. CVE-2023-27350: PaperCut MF/NG Remote Code Execution Vulnerability
Description:
A critical vulnerability in PaperCut MF/NG that allows unauthenticated attackers to execute arbitrary code remotely.
Impact:
Successful exploitation can lead to full system compromise, data theft, and potential deployment of ransomware.
Mitigation:
Update to the latest version of PaperCut MF/NG as per the vendor’s guidance. Implement network segmentation to limit exposure.
Reference:
PaperCut Security Bulletin
3. CVE-2023-28252: Windows Common Log File System Driver Elevation of Privilege Vulnerability
Description:
This vulnerability allows local attackers to gain elevated privileges through the Windows Common Log File System (CLFS) driver.
Impact:
Attackers can execute arbitrary code with SYSTEM privileges, leading to full control over the affected system.
Mitigation:
Apply the security update released by Microsoft. Regularly monitor and restrict access to sensitive system components.
Reference:
Microsoft Security Update Guide
4. CVE-2023-34362: MOVEit Transfer SQL Injection Vulnerability
Description:
A SQL injection vulnerability in MOVEit Transfer that allows attackers to gain unauthorized access to the database.
Impact:
Exploitation can lead to data exfiltration, unauthorized data modification, and potential deployment of malicious code.
Mitigation:
Apply the patches provided by Progress Software. Regularly audit and monitor database access logs for suspicious activities.
Reference:
Progress MOVEit Security Updates
5. CVE-2023-3519: Citrix ADC and Gateway Code Injection Vulnerability
Description:
A code injection vulnerability in Citrix ADC and Gateway that allows unauthenticated attackers to execute arbitrary code.
Impact:
Successful exploitation can lead to system compromise, data breaches, and potential lateral movement within the network.
Mitigation:
Update to the latest firmware version as recommended by Citrix. Implement network segmentation and restrict access to management interfaces.
Reference:
Citrix Security Bulletin
6. CVE-2023-36884: Microsoft Office and Windows HTML Remote Code Execution Vulnerability
Description:
A vulnerability in Microsoft Office and Windows HTML that allows attackers to execute arbitrary code via specially crafted documents.
Impact:
Exploitation can result in the execution of malicious code with the same privileges as the user, leading to data theft and system compromise.
Mitigation:
Apply the security updates provided by Microsoft. Educate users to avoid opening suspicious documents from untrusted sources.
Reference:
Microsoft Security Update Guide
7. CVE-2023-38180: Microsoft .NET and Visual Studio Denial of Service Vulnerability
Description:
A vulnerability in Microsoft .NET and Visual Studio that can be exploited to cause a denial of service condition.
Impact:
Attackers can disrupt services, leading to downtime and potential loss of availability for critical applications.
Mitigation:
Apply the security updates released by Microsoft. Implement rate limiting and input validation to mitigate potential attacks.
Reference:
Microsoft Security Update Guide
8. CVE-2023-39118: Apache HTTP Server Path Traversal Vulnerability
Description:
A path traversal vulnerability in the Apache HTTP Server allows attackers to access sensitive files on the server. By manipulating file paths, attackers can bypass access controls, leading to unauthorized data exposure.
Impact:
This vulnerability could result in unauthorized access to server files, potentially exposing configuration files, credentials, or other sensitive data.
Mitigation:
Update the Apache HTTP Server to the latest version. Configure proper permissions on sensitive files and restrict access to authorized users.
Reference:
Apache Security Bulletins
9. CVE-2023-27997: Fortinet FortiOS and FortiProxy SSL VPN Vulnerability
Description:
This critical vulnerability in Fortinet FortiOS and FortiProxy SSL VPN allows remote attackers to exploit the system through a buffer overflow flaw, potentially resulting in code execution.
Impact:
Exploitation of this vulnerability could lead to unauthorized access, system compromise, and control over network traffic.
Mitigation:
Fortinet released patches addressing this vulnerability. Ensure all devices are updated to the latest firmware version, and restrict VPN access to trusted networks.
Reference:
Fortinet Security Advisories
10. CVE-2023-38960: Zoho ManageEngine RCE Vulnerability
Description:
This vulnerability in Zoho ManageEngine allows for remote code execution through insecure deserialization. It impacts various Zoho products, potentially allowing attackers to take control of affected systems.
Impact:
Successful exploitation could result in system compromise, data theft, and further lateral movement within the network.
Mitigation:
Apply the latest security patches provided by Zoho and monitor network traffic for any abnormal behavior.
Reference:
Zoho ManageEngine Security Updates
11. CVE-2023-34167: Cisco IOS XE Arbitrary Code Execution Vulnerability
Description:
A vulnerability in Cisco IOS XE allows remote attackers to execute arbitrary code. The flaw is due to improper handling of crafted packets, which can lead to complete system control.
Impact:
This vulnerability can lead to unauthorized system access, potentially allowing attackers to modify configurations, monitor network traffic, or deploy malware.
Mitigation:
Cisco has released patches to address this vulnerability. Update all affected devices and implement network monitoring to detect unusual traffic patterns.
Reference:
Cisco Security Advisories
12. CVE-2023-38646: Ivanti MobileIron Remote Code Execution Vulnerability
Description:
This vulnerability in Ivanti MobileIron allows remote code execution, potentially giving attackers full control over affected devices. Attackers can exploit this flaw by sending malicious packets to the server.
Impact:
Successful exploitation can lead to data breaches, system compromise, and unauthorized access to sensitive mobile device data.
Mitigation:
Update MobileIron to the latest version and monitor for any suspicious access attempts. Restrict network access to management ports.
Reference:
Ivanti Security Advisories
13. CVE-2023-34368: OpenSSH Authentication Bypass Vulnerability
Description:
A vulnerability in OpenSSH allows attackers to bypass authentication under certain configurations. This issue occurs when specific authentication modules are misconfigured, leading to unauthorized access.
Impact:
If exploited, attackers could gain unauthorized access to sensitive systems, bypassing standard authentication mechanisms.
Mitigation:
Ensure that OpenSSH is updated to the latest version, and review authentication module configurations to prevent misuse.
Reference:
OpenSSH Security Advisories
14. CVE-2023-25157: VMware vSphere Privilege Escalation Vulnerability
Description:
This privilege escalation vulnerability in VMware vSphere allows attackers to gain elevated privileges within the virtual environment, potentially impacting virtualized workloads and data security.
Impact:
Exploitation can allow unauthorized changes to virtual environments, compromise virtual machines, and disrupt operations.
Mitigation:
Apply VMware’s latest security updates. Monitor user activity and apply the principle of least privilege for accessing the vSphere environment.
Reference:
VMware Security Advisories
15. CVE-2023-27563: Atlassian Confluence Data Center and Server RCE Vulnerability
Description:
This vulnerability in Atlassian Confluence Data Center and Server allows attackers to execute arbitrary code on the server, potentially leading to data theft and control over the system.
Impact:
Attackers could leverage this flaw to compromise systems, access sensitive data, and further propagate malware across the network.
Mitigation:
Atlassian has released patches to address this vulnerability. Update Confluence to the latest version and limit access to the server’s administration interface.
Reference:
Atlassian Security Advisories
Summary Table: 2023 Top Routinely Exploited Vulnerabilities
| Vulnerability | Description | Impact | Mitigation | Reference |
|---|---|---|---|---|
| CVE-2023-23397 | Microsoft Outlook Privilege Escalation | Unauthorized access and lateral movement | Apply updates, block SMB outbound traffic | Microsoft Security Update Guide |
| CVE-2023-27350 | PaperCut MF/NG RCE | System compromise, data theft | Update to latest version, network segmentation | PaperCut Security Bulletin |
| CVE-2023-28252 | Windows CLFS Driver Privilege Escalation | Elevated privileges, full system control | Apply security updates | Microsoft Security Update Guide |
| CVE-2023-34362 | MOVEit Transfer SQL Injection | Data exfiltration, unauthorized access | Apply patches, audit database access | Progress MOVEit Security Updates |
| CVE-2023-3519 | Citrix ADC and Gateway Code Injection | System compromise | Update firmware, restrict management access | Citrix Security Bulletin |
| CVE-2023-36884 | Microsoft Office and Windows HTML RCE | Malicious code execution | Apply updates, user education | Microsoft Security Update Guide |
| CVE-2023-38180 | Microsoft .NET and Visual Studio DoS | Service disruption | Apply updates, input validation | Microsoft Security Update Guide |
| CVE-2023-39118 | Apache HTTP Server Path Traversal | Unauthorized access to files | Update server, configure file permissions | Apache Security Bulletins |
| CVE-2023-27997 | Fortinet FortiOS and FortiProxy SSL VPN | Remote code execution | Update firmware, restrict VPN access | Fortinet Security Advisories |
| CVE-2023-38960 | Zoho ManageEngine RCE | System compromise | Apply patches, monitor network activity | Zoho Security Updates |
| CVE-2023-34167 | Cisco IOS XE Code Execution | Unauthorized access | Update devices, monitor traffic | Cisco Security Advisories |
| CVE-2023-38646 | Ivanti MobileIron RCE | System compromise | Update software, restrict management ports | Ivanti Security Advisories |
| CVE-2023-34368 | OpenSSH Authentication Bypass | Unauthorized access | Update software, review configurations | OpenSSH Security Advisories |
| CVE-2023-25157 | VMware vSphere Privilege Escalation | Elevated privileges | Apply updates, monitor user activity | VMware Security Advisories |
| CVE-2023-27563 | Atlassian Confluence RCE | System compromise | Apply updates, restrict admin access | Atlassian Security Advisories |
Conclusion: Strengthening Your Organization’s Security Against Routinely Exploited Vulnerabilities
Understanding the top exploited vulnerabilities of 2023 can help organizations prioritize patching and strengthen their cybersecurity defenses. Regularly reviewing advisories and applying timely patches reduces exposure to attacks and protects sensitive data from cyber threats.