CVE-2017-11876 in SharePoint Enterprise Server
Summary
by MITRE
Microsoft Project Server and Microsoft SharePoint Enterprise Server 2016 allow an attacker to use cross-site forgery to read content that they are not authorized to read, use the victim's identity to take actions on the web application on behalf of the victim, such as change permissions and delete content, and inject malicious content in the browser of the victim, aka "Microsoft Project Server Elevation of Privilege Vulnerability".
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Analysis
by VulDB Data Team • 01/23/2021
This vulnerability represents a critical cross-site request forgery flaw in Microsoft Project Server and SharePoint Enterprise Server 2016 that enables attackers to perform unauthorized actions through victim sessions. The issue stems from insufficient validation of cross-site requests, allowing malicious actors to craft requests that appear to originate from legitimate users within the target organization. This weakness falls under the CWE-352 category of Cross-Site Request Forgery, where the application fails to properly verify the source of requests and validate user authorization. The vulnerability specifically affects the authentication and authorization mechanisms of these Microsoft server products, creating a pathway for privilege escalation and unauthorized access to sensitive information and functionalities.
The technical exploitation of this vulnerability occurs when an attacker crafts malicious web requests that leverage the victim's authenticated session to perform actions within the targeted applications. Since the applications do not adequately validate the origin of requests or implement proper anti-CSRF tokens, the server processes these forged requests as legitimate transactions. This allows attackers to execute operations such as modifying user permissions, deleting content, and injecting malicious scripts into the victim's browser environment. The impact extends beyond simple data theft as attackers can effectively impersonate legitimate users and perform administrative functions within the SharePoint and Project Server environments.
From an operational perspective, this vulnerability poses significant risks to enterprise security infrastructure as it enables attackers to bypass traditional access controls and elevate privileges within the Microsoft server ecosystem. Organizations using these products face potential data breaches, unauthorized modifications to critical business information, and possible complete compromise of their project management and document sharing platforms. The vulnerability is particularly dangerous because it can be exploited through social engineering techniques where victims are tricked into clicking malicious links or visiting compromised websites. The attack vector typically involves phishing campaigns or compromised websites that deliver malicious content to unsuspecting users who are authenticated to the target applications.
Mitigation strategies for this vulnerability should include implementing proper anti-CSRF token mechanisms within the applications, ensuring that all requests are validated against legitimate user sessions, and configuring appropriate access controls and authorization checks. Organizations should deploy web application firewalls to detect and block suspicious cross-site requests, apply the latest security patches from Microsoft, and conduct regular security assessments of their SharePoint and Project Server implementations. The mitigation approach aligns with ATT&CK technique T1078 which addresses valid accounts and privilege escalation, as well as T1566 which covers social engineering tactics. Network segmentation and monitoring solutions should be deployed to detect anomalous access patterns and unauthorized modifications to sensitive content within the affected systems.