CVE-2021-28474 is a remote code execution vulnerability that affects Microsoft SharePoint Server and SharePoint Foundation. This vulnerability allows attackers to execute arbitrary code on the affected systems, which could lead to severe consequences such as unauthorized access to sensitive data and complete system compromise. The vulnerability has a CVSS score of 8.8, categorizing it as high severity, which highlights the urgency for organizations to address this issue promptly.
Risk to organizations includes potential exploitation over the network with low complexity and minimal privileges required. Given its high impact on confidentiality, integrity, and availability, organizations must take immediate action to mitigate the risk. The vulnerability was published on May 11, 2021, and has been modified since its initial disclosure.
As of now, there are no known public exploits available, and it is not listed in the Known Exploited Vulnerabilities (KEV) catalog. However, organizations should not be complacent, as attackers may develop exploits in the future. Therefore, organizations should prioritize patching immediately.
Organizations using affected versions of Microsoft SharePoint should ensure they are following best practices for vulnerability management and are prepared to apply security updates as they become available.
Vulnerability Details
The CVE-2021-28474 vulnerability allows for remote code execution in Microsoft SharePoint Server. The official CVE description states that it can be exploited if an attacker sends specially crafted requests to an affected SharePoint server. The attack vector is classified as network-based, and it requires low complexity, with the attacker needing only low privileges to exploit the vulnerability. There is no user interaction required, making it particularly dangerous.
The CVSS score of 8.8 indicates a high severity level, with high impacts on confidentiality, integrity, and availability. The affected products include SharePoint Foundation 2013 SP1, SharePoint Server 2016 Enterprise, and SharePoint Server 2019. The vulnerability was disclosed on May 11, 2021, and is classified under CWE-436.
Technical Analysis
The root cause of CVE-2021-28474 stems from insufficient validation of user-supplied input, which allows an attacker to craft requests that can execute arbitrary code. This vulnerability can be exploited over the network, making it critical for organizations to implement network security measures to mitigate risks.
Attack complexity is low, indicating that attackers can exploit the vulnerability without significant effort. The required privileges are also low, which means that even users with minimal access rights can execute the attack. Importantly, no user interaction is required, making this vulnerability particularly insidious.
The impacts of exploitation include high confidentiality, integrity, and availability risks, as an attacker could potentially gain complete control of the affected system.
Risk & Impact Analysis
The real-world deployment risk associated with CVE-2021-28474 is significant. Organizations utilizing Microsoft SharePoint products must recognize that this vulnerability poses a threat of remote code execution that could be exploited by malicious actors. The blast radius potential is broad, affecting any environment running the vulnerable software versions.
Organizations should address this vulnerability in their priority patch cycle due to its high CVSS score and the potential impacts on their operations. The urgency for remediation is further emphasized by the rising trend of remote code execution vulnerabilities being targeted by attackers in modern cyber threats.
The EPSS score of 0.14 indicates a probability of exploitation, placing organizations in the highest percentile of risk. This means that organizations should not only prioritize patching immediately but also actively monitor their environments for signs of exploitation.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The affected versions of Microsoft SharePoint include:
• SharePoint Foundation 2013 SP1
• SharePoint Server 2016 Enterprise
• SharePoint Server 2019
Mitigation & Remediation
To mitigate the risks associated with CVE-2021-28474, organizations should apply the latest security patches provided by Microsoft. It is critical to ensure that all affected products are updated to the latest versions. For more information on patching, organizations can refer to the Microsoft Security Response Center's advisory on this vulnerability.
Organizations may also consider implementing network controls to limit exposure to vulnerable systems, including firewall rules and segmentation strategies. Additionally, continuous security testing can help identify weaknesses and validate remediation efforts.
Continuous security testing is essential for maintaining a secure environment and should be part of any organization's security strategy.
Detection Guidance
Organizations should monitor logs for indicators of exploitation attempts, including unusual access patterns or unauthorized requests targeting SharePoint services. Behavioral anomalies in server performance and unexpected application errors may also indicate potential exploitation.
Implementing network signatures that detect known patterns of attack can aid in identifying attempts to exploit this vulnerability. Regularly reviewing system changes can also help catch unauthorized modifications indicative of exploitation.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2021-28474 lies in its representation of the ongoing challenges organizations face with remote code execution vulnerabilities. As cyber threats evolve, the ability to exploit such vulnerabilities continues to be a primary concern for security teams.
This vulnerability underscores the importance of maintaining secure coding practices and robust testing methodologies to prevent similar weaknesses. Organizations should also review their security posture and ensure that vulnerability management protocols are effectively implemented.
For further reading on vulnerability management and penetration testing best practices, organizations can refer to the following resources:
Vulnerability management program design and penetration testing methodology are critical components of an effective security framework.
Lastly, organizations should remain vigilant and adapt their security strategies to the changing threat landscape to mitigate risks associated with vulnerabilities like CVE-2021-28474.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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