The Cybersecurity and Infrastructure Security Agency (CISA), National Security Agency (NSA), and Federal Bureau of Investigation (FBI) have jointly released a critical cybersecurity advisory detailing the 15 most routinely exploited vulnerabilities in 2023.
This collaborative effort, which also involved cybersecurity agencies from Australia, Canada, New Zealand, and the United Kingdom, aims to alert organizations to the most pressing cyber threats and provide guidance on mitigating these risks.
The advisory reveals a concerning trend: malicious actors exploited more zero-day vulnerabilities to compromise enterprise networks in 2023 compared to the previous year. This shift allowed cybercriminals to conduct operations against high-priority targets with increased effectiveness.
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Topping the list is CVE-2023-3519, a vulnerability affecting Citrix NetScaler ADC and NetScaler Gateway. This flaw allows unauthenticated users to cause a stack buffer overflow, potentially leading to remote code execution.
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Other critical vulnerabilities include CVE-2023-4966 (also affecting Citrix products), CVE-2023-20198 and CVE-2023-20273 (both impacting Cisco IOS XE), and CVE-2023-27997 (affecting Fortinet FortiOS and FortiProxy SSL-VPN).
The list also includes the infamous Log4Shell vulnerability (CVE-2021-44228), which continues to be exploited despite being disclosed in December 2021. This underscores the persistence of certain vulnerabilities and the importance of timely patching.
Here’s a table summarizing the 15 critical vulnerabilities most routinely exploited in 2023, based on the information provided in the advisory:
| CVE | Vendor | Product(s) | Vulnerability Type |
|---|---|---|---|
| CVE-2023-3519 | Citrix | NetScaler ADC, NetScaler Gateway | Code Injection |
| CVE-2023-4966 | Citrix | NetScaler ADC, NetScaler Gateway | Buffer Overflow |
| CVE-2023-20198 | Cisco | IOS XE Web UI | Privilege Escalation |
| CVE-2023-20273 | Cisco | IOS XE | Web UI Command Injection |
| CVE-2023-27997 | Fortinet | FortiOS, FortiProxy SSL-VPN | Heap-Based Buffer Overflow |
| CVE-2023-34362 | Progress | MOVEit Transfer | SQL Injection |
| CVE-2023-22515 | Atlassian | Confluence Data Center and Server | Broken Access Control |
| CVE-2021-44228 (Log4Shell) | Apache | Log4j2 | Remote Code Execution (RCE) |
| CVE-2023-2868 | Barracuda Networks | ESG Appliance | Improper Input Validation |
| CVE-2022-47966 | Zoho | ManageEngine Multiple Products | Remote Code Execution |
| CVE-2023-27350 | PaperCut | MF/NG | Improper Access Control |
| CVE-2020-1472 | Microsoft | Netlogon | Privilege Escalation |
| CVE-2023-42793 | JetBrains | TeamCity | Authentication Bypass |
| CVE-2023-23397 | Microsoft | Office Outlook | Privilege Escalation |
| CVE-2023-49103 | ownCloud | graphapi | Information Disclosure |
The agencies strongly urge vendors, developers, and end-user organizations to implement a range of mitigations. For software creators, recommendations include adopting secure-by-design principles, implementing robust testing environments, and establishing coordinated vulnerability disclosure programs.
End-user organizations are advised to apply timely patches, implement centralized patch management systems, and utilize advanced security tools such as endpoint detection and response (EDR) solutions.
CISA Director Jen Easterly emphasized the critical nature of this advisory, stating, “This joint effort highlights the global nature of cyber threats and the need for international cooperation in cybersecurity. We urge all organizations to review this advisory and take immediate action to secure their systems.”
The advisory also provides detailed technical information on each vulnerability, including the affected products, vulnerability types, and associated Common Weakness Enumerations (CWEs).
This comprehensive approach aims to equip cybersecurity professionals with the knowledge needed to prioritize their defense strategies effectively.
As cyber threats continue to evolve, this collaborative advisory serves as a crucial resource for organizations worldwide. By focusing on these top exploited vulnerabilities, businesses, and government entities can better allocate their cybersecurity resources and strengthen their overall security posture against the most pressing digital threats of 2023.
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