Horizon Alert
Summary of the vulnerability and why it matters
Improper handling of web page input in Microsoft Office SharePoint could allow an attacker to elevate their privileges across a network. This vulnerability is rated as CRITICAL and has a high potential for external exploitation due to the nature of SharePoint deployments.
- Web input errors in SharePoint enable privilege escalation.
- Critical issue with external access potential.
- Confirm relevance and exposure of SharePoint.
Attack Path
How an attacker could exploit the issue
An attacker could reach an authorized user of Microsoft Office SharePoint through a network connection. By tricking the user into interacting with a specially crafted web page, the attacker could trigger a cross-site scripting vulnerability. If successful, this could allow the attacker to gain elevated privileges on the system.
- Requires network access and authorized user.
- Triggered by user interaction with malicious web page.
- Risk of unauthorized privilege escalation.
Live Threat
Current exploitation, exposure, and threat context
This vulnerability could allow an authorized attacker to elevate their privileges over a network. This is possible when a user interacts with a specially crafted web page, potentially leading to the execution of unauthorized actions within the affected system.
- Authorized user account.
- Malicious web page interaction.
- Privilege escalation.
Operational Fix
Recommended remediation, mitigation, and detection steps
This critical cross-site scripting vulnerability in Microsoft Office SharePoint allows an authenticated attacker to elevate privileges. Given SharePoint's common use as an internet-facing platform for collaboration and remote access, teams responsible for its infrastructure, security, and application ownership must prioritize understanding its exposure. The immediate first step is to inventory all SharePoint instances, confirm their accessibility and business criticality, and identify the accountable system owner to develop a targeted remediation plan.
- SharePoint infrastructure and application owners.
- Verify external reachability and business criticality.
- Plan targeted remediation based on risk.
