{"id":18515,"date":"2026-09-15T06:03:51","date_gmt":"2026-09-14T21:03:51","guid":{"rendered":"https:\/\/m365jp.net\/?p=18515"},"modified":"2026-09-15T06:15:03","modified_gmt":"2026-09-14T21:15:03","slug":"mc1471963-30-day-reminder-ad-fs-dkm-container-acl-hardening-begins-in-october-2026","status":"publish","type":"post","link":"https:\/\/m365jp.net\/index.php\/2026-09-15-mc1471963-30-day-reminder-ad-fs-dkm-container-acl-hardening-begins-in-october-2026","title":{"rendered":"MC1471963 | 30-Day Reminder: AD FS DKM container ACL hardening begins in October 2026"},"content":{"rendered":"<div class=\"postie-post\">\n<div>\n<hr>\n<table id=\"section\">\n<tbody>\n<tr>\n<th width=\"95%\">MC1471963 | 30-Day Reminder: AD FS DKM container ACL hardening begins in October 2026<\/th>\n<\/tr>\n<\/tbody>\n<\/table>\n<hr>\n<table id=\"data\">\n<tbody>\n<tr>\n<th>Classification<\/th>\n<td>stayInformed<\/td>\n<\/tr>\n<tr>\n<th>Last Updated<\/th>\n<td>09\/14\/2026 20:56:15<\/td>\n<\/tr>\n<tr>\n<th>Start Time<\/th>\n<td>09\/14\/2026 20:56:14<\/td>\n<\/tr>\n<tr>\n<th>End Time<\/th>\n<td>09\/14\/2027 20:56:14<\/td>\n<\/tr>\n<tr>\n<th>Message Content<\/th>\n<td>\n<div><b>What and why<\/b><\/div>\n<div>In October 2026, Windows updates will begin Enforcement mode for AD FS Distributed Key Manager (DKM) container ACL hardening. This hardening change is designed to address the elevation of privilege vulnerability documented in  <a href=\"https:\/\/msrc.microsoft.com\/update-guide\/vulnerability\/CVE-2026-56155\" rel=\"noopener noreferrer\" target=\"_blank\">  CVE-2026-56155<\/a> by automatically remediating insecure DKM container ACL configurations on supported Windows Server versions.<\/div>\n<div>  <\/div>\n<div>If your organization uses Active Directory Federation Services (AD FS), use the remaining Audit mode period to validate DKM container permissions, identify compatibility issues, and complete preparation before Enforcement mode begins.<\/div>\n<div>  <\/div>\n<div><b>Rollout schedule<\/b><\/div>\n<div>Enforcement mode begins with the October 2026 Windows security update.<\/div>\n<div>  <\/div>\n<div><b>Impact on your organization<\/b><\/div>\n<div>Organizations using AD FS might see changes to DKM container permissions when remediation is applied during Enforcement mode. During the October 2026 update, supported Windows Server versions will run remediation by default unless administrators explicitly   opt out. Windows Server 2012 and Windows Server 2012 R2 still require manual remediation and will not be automatically remediated.<\/div>\n<div>  <\/div>\n<div><b>Action required\/recommendations<\/b><\/div>\n<div>Organizations using AD FS should:<\/div>\n<ul>\n<li>Install the <a href=\"https:\/\/msrc.microsoft.com\/update-guide\/vulnerability\/CVE-2026-56155\" rel=\"noopener noreferrer\" target=\"_blank\">  July 14, 2026 Windows security update<\/a> or a later Windows update on AD FS servers.<\/li>\n<li>Review AD FS Admin event logs for Event ID 1132, which indicates that DKM container permissions require attention.<\/li>\n<li>Test remediation during the current Audit mode phase and address findings before Enforcement mode begins in October 2026.<\/li>\n<li>See the guidance in: <a href=\"https:\/\/support.microsoft.com\/servicing\/os\/windows\/docs\/2026\/07\/kb5121391-cve-2026-56155-ad-fs-dkm-container-acl-hardening\" rel=\"noopener noreferrer\" target=\"_blank\">  CVE-2026-56155: AD FS Distributed Key Manager container ACL hardening<\/a>.<\/li>\n<\/ul>\n<\/td>\n<\/tr>\n<tr>\n<th>Machine Translation<\/th>\n<td>\n<div><b>\u4f55\u3068\u306a\u305c<\/b><\/div>\n<div>2026\u5e7410\u6708\u304b\u3089\u3001Windows \u30a2\u30c3\u30d7\u30c7\u30fc\u30c8\u306fAD FS Distributed Key Manager(DKM)\u30b3\u30f3\u30c6\u30caACL\u30cf\u30fc\u30c9\u30cb\u30f3\u30b0\u306eEnforcement\u30e2\u30fc\u30c9\u3092\u958b\u59cb\u3057\u307e\u3059\u3002\u3053\u306e\u30cf\u30fc\u30c9\u30cb\u30f3\u30b0\u5909\u66f4\u306f\u3001\u30b5\u30dd\u30fc\u30c8\u3055\u308c\u308bWindows Server\u30d0\u30fc\u30b8\u30e7\u30f3\u3067\u30bb\u30ad\u30e5\u30ea\u30c6\u30a3\u306e\u60aa\u3044DKM\u30b3\u30f3\u30c6\u30caACL\u69cb\u6210\u3092\u81ea\u52d5\u7684\u306b\u4fee\u5fa9\u3059\u308b\u3053\u3068\u3067\u3001  <a href=\"https:\/\/msrc.microsoft.com\/update-guide\/vulnerability\/CVE-2026-56155\" rel=\"noopener noreferrer\" target=\"_blank\">  CVE-2026-56155<\/a> \u306b\u8a18\u8f09\u3055\u308c\u305f\u6a29\u9650\u6607\u683c\u8106\u5f31\u6027\u306b\u5bfe\u5fdc\u3059\u308b\u3053\u3068\u3092\u76ee\u7684\u3068\u3057\u3066\u3044\u307e\u3059\u3002<\/div>\n<div>  <\/div>\n<div>\u7d44\u7e54\u304cActive Directory Federation Services(AD FS)\u3092\u4f7f\u7528\u3057\u3066\u3044\u308b\u5834\u5408\u306f\u3001\u6b8b\u308a\u306e\u76e3\u67fb\u671f\u9593\u3092\u4f7f\u3063\u3066DKM\u30b3\u30f3\u30c6\u30ca\u6a29\u9650\u306e\u691c\u8a3c\u3001\u4e92\u63db\u6027\u306e\u554f\u984c\u306e\u7279\u5b9a\u3001\u5f37\u5236\u30e2\u30fc\u30c9\u958b\u59cb\u524d\u306e\u6e96\u5099\u3092\u5b8c\u4e86\u3057\u3066\u304f\u3060\u3055\u3044\u3002<\/div>\n<div>  <\/div>\n<div><b>\u5c55\u958b\u30b9\u30b1\u30b8\u30e5\u30fc\u30eb<\/b><\/div>\n<div>\u5f37\u5236\u30e2\u30fc\u30c9\u306f2026\u5e7410\u6708\u306eWindows\u30bb\u30ad\u30e5\u30ea\u30c6\u30a3\u30a2\u30c3\u30d7\u30c7\u30fc\u30c8\u304b\u3089\u59cb\u307e\u308a\u307e\u3059\u3002<\/div>\n<div>  <\/div>\n<div><b>\u7d44\u7e54\u3078\u306e\u5f71\u97ff<\/b><\/div>\n<div>AD FS\u3092\u4f7f\u7528\u3057\u3066\u3044\u308b\u7d44\u7e54\u306f\u3001\u5f37\u5236\u30e2\u30fc\u30c9\u3067\u306e\u88dc\u6b63\u304c\u9069\u7528\u3055\u308c\u308b\u969b\u306bDKM\u30b3\u30f3\u30c6\u30ca\u6a29\u9650\u306e\u5909\u66f4\u3092\u898b\u308b\u3053\u3068\u304c\u3042\u308a\u307e\u3059\u30022026\u5e7410\u6708\u306e\u30a2\u30c3\u30d7\u30c7\u30fc\u30c8\u3067\u306f\u3001\u7ba1\u7406\u8005\u304c\u660e\u793a\u7684\u306b\u30aa\u30d7\u30c8\u30a2\u30a6\u30c8\u3057\u306a\u3044\u9650\u308a\u3001\u30b5\u30dd\u30fc\u30c8\u3055\u308c\u3066\u3044\u308bWindows Server\u30d0\u30fc\u30b8\u30e7\u30f3\u306f\u30c7\u30d5\u30a9\u30eb\u30c8\u3067\u88dc\u4e01\u3092\u5b9f\u884c\u3057\u307e\u3059\u3002Windows Server 2012\u304a\u3088\u3073Windows Server 2012 R2\u306f\u4f9d\u7136\u3068\u3057\u3066\u624b\u52d5\u88dc\u4e01\u304c\u5fc5\u8981\u3067\u3042\u308a\u3001\u81ea\u52d5\u3067\u88dc\u4e01\u3055\u308c\u308b\u3053\u3068\u306f\u3042\u308a\u307e\u305b\u3093\u3002<\/div>\n<div>  <\/div>\n<div><b>\u5fc5\u8981\u306a\u884c\u52d5\/\u63d0\u8a00<\/b><\/div>\n<div>AD FS\u3092\u4f7f\u7528\u3059\u308b\u7d44\u7e54\u306f\u4ee5\u4e0b\u306e\u3053\u3068\u3092\u3059\u3079\u304d\u3067\u3059:<\/div>\n<ul>\n<li><a href=\"https:\/\/msrc.microsoft.com\/update-guide\/vulnerability\/CVE-2026-56155\" rel=\"noopener noreferrer\" target=\"_blank\">2026\u5e747\u670814\u65e5\u306eWindows\u30bb\u30ad\u30e5\u30ea\u30c6\u30a3\u30a2\u30c3\u30d7\u30c7\u30fc\u30c8<\/a>\u307e\u305f\u306f\u305d\u308c\u4ee5\u964d\u306eWindows\u30a2\u30c3\u30d7\u30c7\u30fc\u30c8\u3092AD FS\u30b5\u30fc\u30d0\u30fc\u306b\u30a4\u30f3\u30b9\u30c8\u30fc\u30eb\u3057\u3066\u304f\u3060\u3055\u3044\u3002<\/li>\n<li>AD FS\u306e\u7ba1\u7406\u30a4\u30d9\u30f3\u30c8\u30ed\u30b0\u3067Event ID 1132\u3092\u78ba\u8a8d\u3057\u3001DKM\u30b3\u30f3\u30c6\u30ca\u6a29\u9650\u306b\u6ce8\u610f\u304c\u5fc5\u8981\u3067\u3042\u308b\u3053\u3068\u3092\u793a\u3057\u307e\u3059\u3002<\/li>\n<li>\u73fe\u5728\u306e\u76e3\u67fb\u30e2\u30fc\u30c9\u6bb5\u968e\u3067\u306e\u4fee\u5fa9\u30c6\u30b9\u30c8\u3092\u884c\u3044\u30012026\u5e7410\u6708\u306e\u57f7\u884c\u30e2\u30fc\u30c9\u958b\u59cb\u524d\u306b\u8abf\u67fb\u7d50\u679c\u306b\u5bfe\u51e6\u3057\u307e\u3059\u3002<\/li>\n<li>\u30ac\u30a4\u30c0\u30f3\u30b9\u306f\u4ee5\u4e0b\u306e\u901a\u308a\u3067\u3059: <a href=\"https:\/\/support.microsoft.com\/servicing\/os\/windows\/docs\/2026\/07\/kb5121391-cve-2026-56155-ad-fs-dkm-container-acl-hardening\" rel=\"noopener noreferrer\" target=\"_blank\">  CVE-2026-56155: AD FS Distributed Key Manager \u30b3\u30f3\u30c6\u30ca ACL \u30cf\u30fc\u30c9\u30cb\u30f3\u30b0<\/a>\u3002<\/li>\n<\/ul>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table><\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>MC1471963 | 30-Day Reminder: AD FS DKM container ACL hardening begins in October 2026 Classification stayInfor [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-18515","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/posts\/18515","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/comments?post=18515"}],"version-history":[{"count":0,"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/posts\/18515\/revisions"}],"wp:attachment":[{"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/media?parent=18515"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/categories?post=18515"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/tags?post=18515"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}