What happened
The threat actor known as APT28 has been observed actively exploiting a Microsoft Office 0-day vulnerability to compromise targeted systems. According to the report, security researchers identified that the 0-day flaw in Microsoft Office was being abused in the wild as part of a broader malicious campaign. The vulnerability allows specially crafted Office documents to trigger arbitrary code execution when opened by vulnerable versions of the application. Once exploited, the malicious payload can execute without additional user interaction beyond document opening. APT28, which is widely tracked as a Russian-aligned threat group, incorporated this Office 0-day into spear-phishing lures sent to selected recipients. The activity was detected through telemetry showing exploitation attempts correlating with known APT28 targeting patterns.
Who is affected
Organizations and users who open malicious Microsoft Office documents from untrusted senders are directly at risk of compromise via the actively exploited 0-day being used by APT28.
Why CISOs should care
The integration of a zero-day Office exploit into targeted operations by APT28 underscores ongoing risk from sophisticated threat actors combining novel vulnerabilities with spear-phishing to achieve initial access and code execution inside enterprise environments.
3 practical actions
- Review Office patch status. Ensure systems are updated with the latest security patches addressing the reported 0-day.
- Scan email attachments for exploit indicators. Inspect incoming Office files for patterns associated with the active campaign.
- Reinforce safe document handling policies. Remind users not to open Office documents from unverified or unexpected sources.