2026年5月26日の
セキュリティ情報

Subject: [Info] CERT-In Recommendation for 12-Hour Patching of Internet-Facing Flaws

Dear Team,

We are sharing a new security guideline issued by CERT-In regarding the acceleration of patching cycles.

■ Overview
Due to the rise of AI-assisted cyber exploitation, the time required for adversaries to identify and weaponize vulnerabilities has decreased significantly. Consequently, CERT-In recommends patching critical vulnerabilities in internet-exposed systems within 12 hours where feasible.

■ Scope
- All internet-facing servers, APIs, cloud ecosystems, and interconnected digital infrastructure.

■ Recommended Actions
1. Review and update the inventory of all internet-exposed assets.
2. Optimize the vulnerability management workflow to reduce the time between disclosure and remediation.
3. Implement compensating controls (e.g., WAF, IPS) to mitigate risks when immediate patching is not possible.

■ Reference
- CERT-In official blueprint

Priority: High
Deadline: Immediate review of patching SLAs

Subject: [Action Required] Please Update Windows and Microsoft Products

Hi everyone,
Microsoft has released critical security updates for Windows and other Office products to fix vulnerabilities that could allow unauthorized access to your system.

What we need you to do:
1. Run Windows Update to ensure your system is up to date.
2. Apply any pending updates for Microsoft Office or other Microsoft applications.

Deadline: By the end of this week

件名: 【共有】Microsoft 2025年1月セキュリティ更新プログラムへの対応について

お疲れさまです。Microsoftの月例パッチに関する情報共有です。

■ 概要
159件の脆弱性が修正されました。特にHyper-V NT Kernel Integration VSPの権限昇格脆弱性（CVE-2025-21333/21334/21335）はCVSS 7.8であり、既に野外での悪用が確認されています。成功した場合、攻撃者はSYSTEM権限を取得可能です。

■ 影響範囲
- Windows, Microsoft Office, Microsoft Visual Studio, Azure, Microsoft Dynamics, Microsoft Edge

■ 対応手順
1. 資産管理ツールまたはWSUS等を用いて、最新の累積更新プログラムを配布・適用する。
2. 特にHyper-V環境を運用しているサーバーの適用状況を優先的に確認する。

■ 参考情報
- Microsoft Security Update Guide: https://msrc.microsoft.com/update-guide/en-us/releaseNote/2025-Jan

対応優先度: 高
対応期限: 速やかに

Subject: [Technical Alert] Microsoft January 2025 Security Updates

Dear Team,

Microsoft has released security updates addressing 159 vulnerabilities. Of particular concern are the privilege escalation flaws in Windows Hyper-V NT Kernel Integration VSP (CVE-2025-21333, CVE-2025-21334, CVE-2025-21335), which are actively being exploited in the wild (CVSS 7.8). Successful exploitation allows an authenticated local attacker to gain SYSTEM privileges.

■ Scope
- Windows, Microsoft Office, Microsoft Visual Studio, Azure, Microsoft Dynamics, Microsoft Edge

■ Mitigation Steps
1. Deploy and apply the latest cumulative updates via WSUS, Intune, or other patch management tools.
2. Prioritize patching for systems running Hyper-V due to active exploitation.

■ Reference
- Microsoft Security Update Guide: https://msrc.microsoft.com/update-guide/en-us/releaseNote/2025-Jan

Priority: High
Deadline: Immediate

Subject: [Security Advisory] KnowledgeDeliver LMS CVE-2026-5426 Mitigation

Dear IT Administration Team,

We are sharing critical information regarding a vulnerability in KnowledgeDeliver LMS.

■ Overview
A high-severity vulnerability (CVE-2026-5426, CVSS 7.5) involving hard-coded ASP.NET machine keys has been exploited. This allows unauthenticated remote code execution (RCE) via ViewState deserialization, leading to the deployment of Godzilla web shells and Cobalt Strike Beacons.

■ Scope
- Digital Knowledge KnowledgeDeliver deployments prior to February 24, 2026.

■ Mitigation Steps
1. Apply the latest security patches immediately to update the software version.
2. Conduct a forensic review of the server for unauthorized files (web shells) and suspicious outbound network traffic.

■ Reference
- Google Mandiant / Google Threat Intelligence Group (GTIG) report

Priority: High
Deadline: Immediate

Subject: [Action Required] Please Update Your Windows and Microsoft Products

Hi everyone,
Microsoft has released critical security updates for Windows and other Microsoft products to fix vulnerabilities that could allow unauthorized access to your system.

What we need you to do:
1. Run Windows Update to ensure your OS is up to date.
2. Apply any pending updates for Microsoft Office or other Microsoft applications.

Deadline: By the end of this week

件名: 【共有】Microsoft 2025年4月度セキュリティ更新プログラムへの対応について

お疲れさまです。4月のマイクロソフト社セキュリティ更新に関する情報共有です。

■ 概要
Windows, Office, Azure, Edge, Visual Studio等を含む126件の脆弱性が修正されました。特にCVE-2025-29824（権限昇格）は既に野外での悪用が確認されており、CVSS 7.8と評価されています。また、SharePointのRCE（CVE-2025-29794, CVSS 8.8）等、重要度の高い脆弱性が含まれています。

■ 影響範囲
- Windows OS
- Microsoft Office / SharePoint
- Azure
- Microsoft Edge for iOS
- Microsoft Visual Studio

■ 対応手順
1. 資産管理ツール等を用いて、対象製品のパッチ適用状況を確認する。
2. 未適用の端末に対し、最新の累積更新プログラムを適用させる。
3. 特に特権アカウントを持つサーバーやSharePointサーバーの更新を優先する。

■ 参考情報
- Microsoft Security Update Guide: https://msrc.microsoft.com/update-guide/en-us/releaseNote/2025-Apr

対応優先度: 高
対応期限: 速やかに

Subject: [Technical Alert] Microsoft April 2025 Security Updates

Dear IT Security Team,

Microsoft has released the April 2025 security updates addressing 126 vulnerabilities.

■ Overview
Critical vulnerabilities include CVE-2025-29824 (Privilege Escalation in Windows Common Log File System driver), which is actively exploited in the wild (CVSS 7.8). Additionally, a high-severity RCE in SharePoint (CVE-2025-29794, CVSS 8.8) and RCEs in Remote Desktop Services (CVE-2025-27480, CVE-2025-27482) have been patched.

■ Scope
- Windows OS, Microsoft Office, SharePoint, Azure, Edge for iOS, Visual Studio

■ Mitigation Steps
1. Audit current patch levels across the infrastructure.
2. Deploy the April 2025 cumulative updates to all affected endpoints and servers.
3. Prioritize patching for SharePoint servers and systems with Remote Desktop Services enabled.

■ Reference
- MSRC Release Note: https://msrc.microsoft.com/update-guide/en-us/releaseNote/2025-Apr

Priority: High
Deadline: Immediate

Subject: [Action Required] Please Update Windows and Microsoft Products

Hi everyone,
Microsoft has released critical security updates to fix vulnerabilities in Windows and other Microsoft software.

What we need you to do:
1. Run Windows Update to ensure your system is up to date.
2. Apply any pending updates for Microsoft Office or other Microsoft applications.

Deadline: By the end of this week

件名: 【共有】Microsoft 10月度セキュリティ更新プログラムへの対応について

お疲れさまです。10月のMicrosoftセキュリティ更新に関する情報共有です。

■ 概要
Windows, Office, Azure, Exchange Server等を含む175件の脆弱性が修正されました。うち15件が「Critical」、158件が「Important」に分類されています。特にCVE-2025-24990 (Windows Agere Modem Driver) は、権限昇格が可能であり、既に野外での利用が確認されています（CVSS 7.8）。

■ 影響範囲
- Windows, Microsoft Office, Azure, Apps, Microsoft Exchange Server, Microsoft Visual Studio

■ 対応手順
1. WSUSまたはIntune等の管理ツールを用いて、最新の累積更新プログラムを配信・適用する。
2. 特に特権昇格の脆弱性が含まれるため、サーバーおよびエンドポイントの適用状況を確認する。

■ 参考情報
- Microsoft Security Update Guide: https://msrc.microsoft.com/update-guide/en-us/releaseNote/2025-Oct

対応優先度: 高
対応期限: 速やかに

Subject: [Technical Alert] Microsoft October Security Updates

Dear Team,

Microsoft has released security updates addressing 175 vulnerabilities across Windows, Office, Azure, and Exchange Server.

■ Overview
15 vulnerabilities are rated 'Critical' and 158 as 'Important'. Of particular concern is CVE-2025-24990 (Windows Agere Modem Driver), a privilege escalation flaw (CVSS 7.8) that is currently being exploited in the wild.

■ Scope
- Windows, Microsoft Office, Azure, Apps, Microsoft Exchange Server, Microsoft Visual Studio

■ Mitigation Steps
1. Deploy the latest cumulative updates via WSUS, Intune, or other patch management systems.
2. Prioritize patching for endpoints and servers to mitigate the risk of local privilege escalation.

■ Reference
- Microsoft Security Update Guide: https://msrc.microsoft.com/update-guide/en-us/releaseNote/2025-Oct

Priority: High
Deadline: Immediate