{"id":13768,"date":"2025-11-13T10:01:27","date_gmt":"2025-11-13T01:01:27","guid":{"rendered":"https:\/\/m365jp.net\/?p=13768"},"modified":"2025-11-13T10:02:49","modified_gmt":"2025-11-13T01:02:49","slug":"mc1185464-usage-detected-basic-auth-with-smtp-auth","status":"publish","type":"post","link":"https:\/\/m365jp.net\/index.php\/2025-11-13-mc1185464-usage-detected-basic-auth-with-smtp-auth","title":{"rendered":"MC1185464 | Usage Detected &#8211; Basic Auth with SMTP AUTH"},"content":{"rendered":"<div class=\"postie-post\">\n<div>\n<hr>\n<table id=\"section\">\n<tbody>\n<tr>\n<th width=\"95%\">MC1185464 | Usage Detected &#8211; Basic Auth with SMTP AUTH<\/th>\n<\/tr>\n<\/tbody>\n<\/table>\n<hr>\n<table id=\"data\">\n<tbody>\n<tr>\n<th>Classification<\/th>\n<td>preventOrFixIssue<\/td>\n<\/tr>\n<tr>\n<th>Last Updated<\/th>\n<td>11\/13\/2025 00:30:38<\/td>\n<\/tr>\n<tr>\n<th>Start Time<\/th>\n<td>11\/13\/2025 00:28:01<\/td>\n<\/tr>\n<tr>\n<th>End Time<\/th>\n<td>06\/30\/2026 07:00:00<\/td>\n<\/tr>\n<tr>\n<th>Message Content<\/th>\n<td>\n<p>As announced in MC786329, Exchange Online will permanently remove support for Basic authentication with Client Submission (SMTP AUTH).<\/p>\n<p>You are receiving this post because we observed messages sent using Basic Auth with SMTP AUTH in your tenant between October 20 and October 24, 2025.    <\/p>\n<p>Please review the SMTP AUTH Clients Report (<a href=\"https:\/\/learn.microsoft.com\/en-us\/exchange\/monitoring\/mail-flow-reports\/mfr-smtp-auth-clients-report\">learn.microsoft.com\/en-us\/exchange\/monitoring\/mail-flow-reports\/mfr-smtp-auth-clients-report<\/a>) and filter on Basic Auth to determine your mailboxes that are using Basic Auth and ensure you have migrated   to an alternative solution following the deprecation timeline.  <\/p>\n<p>We will gradually begin rejecting a small percentage of Basic Auth submissions for all tenants on March 1st 2026 increasing to 100% rejections on April 30th 2026, (previously September 2025). After this time, applications and devices will no longer be able   to use Basic auth as an authentication method and must use OAuth when using SMTP AUTH to send email.  <\/p>\n<p>Basic auth is a legacy authentication method that sends usernames and passwords in plain text over the network. This makes it vulnerable to credential theft, phishing, and brute force attacks. To improve the protection of our customers and their data, we   are retiring Basic auth from Client Submission (SMTP AUTH) and encouraging customers to use modern authentication methods that are more secure.  <\/p>\n<p>[When this will happen:]  <\/p>\n<p>We will be making this change beginning March 1st 2026 and completing April 30th 2026, previously September 2025.  <\/p>\n<p>[How this will affect your organization:]  <\/p>\n<p>The Client Submission (SMTP AUTH) endpoints in scope for this change are:  <\/p>\n<ul>\n<li>smtp.office365.com  <\/li>\n<li>smtp-legacy.office365.com  <\/li>\n<\/ul>\n<p>Once Basic auth is permanently disabled, any clients or apps connecting using Basic auth with Client Submission (SMTP AUTH) will receive this response:  <\/p>\n<ul>\n<li>550 5.7.30 Basic authentication is not supported for Client Submission.  <\/li>\n<\/ul>\n<p>[What you need to do to prepare:]  <\/p>\n<p>If your client supports OAuth, follow these steps: <a href=\"https:\/\/learn.microsoft.com\/en-us\/exchange\/client-developer\/legacy-protocols\/how-to-authenticate-an-imap-pop-smtp-application-by-using-oauth\">learn.microsoft.com\/en-us\/exchange\/client-developer\/legacy-protocols\/how-to-authenticate-an-imap-pop-smtp-application-by-using-oauth<\/a>  <\/p>\n<p>If your client doesn\u2019t support OAuth and you must use Basic Auth with Client Submission (SMTP AUTH), you will need to switch to one of the following alternatives before April 2026, previously September 2025:  <\/p>\n<ul>\n<li>If you are using basic authentication with Client Submission (SMTP AUTH) to send emails to recipients internal to your tenant, you can use Microsoft 365 High Volume Email. Please visit this site to learn more:  <a href=\"https:\/\/learn.microsoft.com\/en-us\/Exchange\/mail-flow-best-practices\/high-volume-mails-m365\" target=\"_blank\">  Manage high volume emails for Microsoft 365 Public preview<\/a>  <\/li>\n<li>If you have an Exchange Server on-premises in a hybrid configuration, you can use Basic auth to authenticate with the Exchange Server on-premises or configure the Exchange Server on-premises with a Receive connector that allows anonymous relay on Exchange   servers. Please visit this site to learn more: <a href=\"https:\/\/learn.microsoft.com\/en-us\/exchange\/mail-flow\/connectors\/allow-anonymous-relay?view=exchserver-2019\" target=\"_blank\">  Allow anonymous relay on Exchange servers<\/a>  <\/li>\n<\/ul>\n<p>Regardless of the volume of email, if you must use Basic auth to send email with Exchange Online, then you must use one of the alternatives or a 3P solution.  <\/p>\n<p>We understand that this change requires some adjustments, but we believe that this is a necessary step to enhance the security and reliability of our email service and your data.  <\/p>\n<p>  <\/p>\n<p>  <\/p>\n<\/td>\n<\/tr>\n<tr>\n<th>Machine Translation<\/th>\n<td>\n<p>MC786329 \u5e74\u306b\u767a\u8868\u3055\u308c\u305f\u3088\u3046\u306b\u3001Exchange Online \u306f\u3001\u30af\u30e9\u30a4\u30a2\u30f3\u30c8\u9001\u4fe1\u306b\u3088\u308b\u57fa\u672c\u8a8d\u8a3c (SMTP AUTH) \u306e\u30b5\u30dd\u30fc\u30c8\u3092\u5b8c\u5168\u306b\u524a\u9664\u3057\u307e\u3059\u3002<\/p>\n<p>\u3053\u306e\u6295\u7a3f\u3092\u53d7\u3051\u53d6\u3063\u3066\u3044\u308b\u306e\u306f\u30012025 \u5e74 10 \u6708 20 \u65e5\u304b\u3089 10 \u6708 24 \u65e5\u306e\u9593\u306b\u3001\u30c6\u30ca\u30f3\u30c8\u3067 SMTP AUTH \u3092\u4f7f\u7528\u3057\u305f\u57fa\u672c\u8a8d\u8a3c\u3092\u4f7f\u7528\u3057\u3066\u9001\u4fe1\u3055\u308c\u305f\u30e1\u30c3\u30bb\u30fc\u30b8\u304c\u78ba\u8a8d\u3055\u308c\u305f\u305f\u3081\u3067\u3059\u3002<\/p>\n<p>SMTP AUTH \u30af\u30e9\u30a4\u30a2\u30f3\u30c8 \u30ec\u30dd\u30fc\u30c8 (<a href=\"https:\/\/learn.microsoft.com\/en-us\/exchange\/monitoring\/mail-flow-reports\/mfr-smtp-auth-clients-report\">learn.microsoft.com\/en-us\/exchange\/monitoring\/mail-flow-reports\/mfr-smtp-auth-clients-report<\/a>) \u3092\u78ba\u8a8d\u3057\u3001\u57fa\u672c\u8a8d\u8a3c\u3067\u30d5\u30a3\u30eb\u30bf\u30fc\u51e6\u7406\u3057\u3066\u3001\u57fa\u672c\u8a8d\u8a3c\u3092\u4f7f\u7528\u3057\u3066\u3044\u308b\u30e1\u30fc\u30eb\u30dc\u30c3\u30af\u30b9\u3092\u7279\u5b9a\u3057\u3001\u975e\u63a8\u5968\u306e\u30bf\u30a4\u30e0\u30e9\u30a4\u30f3\u306b\u5f93\u3063\u3066\u4ee3\u66ff\u30bd\u30ea\u30e5\u30fc\u30b7\u30e7\u30f3\u306b\u79fb\u884c\u3057\u305f\u3053\u3068\u3092\u78ba\u8a8d\u3057\u3066\u304f\u3060\u3055\u3044\u3002<\/p>\n<p>2026 \u5e74 3 \u6708 1 \u65e5\u306b\u3059\u3079\u3066\u306e\u30c6\u30ca\u30f3\u30c8\u306e Basic Auth \u9001\u4fe1\u306e\u3054\u304f\u4e00\u90e8\u3092\u6bb5\u968e\u7684\u306b\u62d2\u5426\u3057\u59cb\u3081\u30012026 \u5e74 4 \u6708 30 \u65e5 (\u4ee5\u524d\u306f 2025 \u5e74 9 \u6708) \u306b\u306f 100% \u306e\u62d2\u5426\u306b\u5897\u52a0\u3057\u307e\u3059\u3002\u3053\u306e\u671f\u9593\u3092\u904e\u304e\u308b\u3068\u3001\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u3068\u30c7\u30d0\u30a4\u30b9\u306f\u8a8d\u8a3c\u65b9\u6cd5\u3068\u3057\u3066\u57fa\u672c\u8a8d\u8a3c\u3092\u4f7f\u7528\u3067\u304d\u306a\u304f\u306a\u308a\u3001SMTP \u8a8d\u8a3c\u3092\u4f7f\u7528\u3057\u3066\u96fb\u5b50\u30e1\u30fc\u30eb\u3092\u9001\u4fe1\u3059\u308b\u3068\u304d\u306b OAuth \u3092\u4f7f\u7528\u3059\u308b\u5fc5\u8981\u304c\u3042\u308a\u307e\u3059\u3002<\/p>\n<p>\u57fa\u672c\u8a8d\u8a3c\u306f\u3001\u30e6\u30fc\u30b6\u30fc\u540d\u3068\u30d1\u30b9\u30ef\u30fc\u30c9\u3092\u30cd\u30c3\u30c8\u30ef\u30fc\u30af\u7d4c\u7531\u3067\u30d7\u30ec\u30fc\u30f3\u30c6\u30ad\u30b9\u30c8\u3067\u9001\u4fe1\u3059\u308b\u5f93\u6765\u306e\u8a8d\u8a3c\u65b9\u6cd5\u3067\u3059\u3002\u3053\u308c\u306b\u3088\u308a\u3001\u8cc7\u683c\u60c5\u5831\u306e\u76d7\u96e3\u3001\u30d5\u30a3\u30c3\u30b7\u30f3\u30b0\u3001\u30d6\u30eb\u30fc\u30c8\u30d5\u30a9\u30fc\u30b9\u653b\u6483\u306b\u5bfe\u3057\u3066\u8106\u5f31\u306b\u306a\u308a\u307e\u3059\u3002\u304a\u5ba2\u69d8\u3068\u305d\u306e\u30c7\u30fc\u30bf\u306e\u4fdd\u8b77\u3092\u5f37\u5316\u3059\u308b\u305f\u3081\u306b\u3001\u30af\u30e9\u30a4\u30a2\u30f3\u30c8\u9001\u4fe1\u304b\u3089\u306e\u57fa\u672c\u8a8d\u8a3c (SMTP \u8a8d\u8a3c) \u3092\u5ec3\u6b62\u3057\u3001\u3088\u308a\u5b89\u5168\u306a\u6700\u65b0\u306e\u8a8d\u8a3c\u65b9\u6cd5\u306e\u4f7f\u7528\u3092\u304a\u5ba2\u69d8\u306b\u63a8\u5968\u3057\u307e\u3059\u3002<\/p>\n<p>[\u3053\u308c\u304c\u3044\u3064\u8d77\u3053\u308b\u304b:]<\/p>\n<p>\u3053\u306e\u5909\u66f4\u306f\u30012026\u5e743\u67081\u65e5\u304b\u30892026\u5e744\u670830\u65e5\u307e\u3067\u3001\u4ee5\u524d\u306f2025\u5e749\u6708\u306b\u884c\u308f\u308c\u307e\u3059\u3002<\/p>\n<p>[\u3053\u308c\u304c\u7d44\u7e54\u306b\u3069\u306e\u3088\u3046\u306a\u5f71\u97ff\u3092\u4e0e\u3048\u308b\u304b:]<\/p>\n<p>\u3053\u306e\u5909\u66f4\u306e\u5bfe\u8c61\u3068\u306a\u308b\u30af\u30e9\u30a4\u30a2\u30f3\u30c8\u9001\u4fe1 (SMTP AUTH) \u30a8\u30f3\u30c9\u30dd\u30a4\u30f3\u30c8\u306f\u6b21\u306e\u3068\u304a\u308a\u3067\u3059\u3002<\/p>\n<ul>\n<li>smtp.office365.com<\/li>\n<li>smtp-legacy.office365.com<\/li>\n<\/ul>\n<p>\u57fa\u672c\u8a8d\u8a3c\u304c\u5b8c\u5168\u306b\u7121\u52b9\u306b\u306a\u308b\u3068\u3001\u30af\u30e9\u30a4\u30a2\u30f3\u30c8\u9001\u4fe1\u306b\u3088\u308b\u57fa\u672c\u8a8d\u8a3c (SMTP AUTH) \u3092\u4f7f\u7528\u3057\u3066\u63a5\u7d9a\u3059\u308b\u30af\u30e9\u30a4\u30a2\u30f3\u30c8\u307e\u305f\u306f\u30a2\u30d7\u30ea\u306f\u3001\u6b21\u306e\u5fdc\u7b54\u3092\u53d7\u3051\u53d6\u308a\u307e\u3059\u3002<\/p>\n<ul>\n<li>550 5.7.30 \u57fa\u672c\u8a8d\u8a3c\u306f\u3001\u30af\u30e9\u30a4\u30a2\u30f3\u30c8\u9001\u4fe1\u3067\u306f\u30b5\u30dd\u30fc\u30c8\u3055\u308c\u3066\u3044\u307e\u305b\u3093\u3002<\/li>\n<\/ul>\n<p>[\u6e96\u5099\u306b\u5fc5\u8981\u306a\u3053\u3068:]<\/p>\n<p>\u30af\u30e9\u30a4\u30a2\u30f3\u30c8\u304c OAuth \u3092\u30b5\u30dd\u30fc\u30c8\u3057\u3066\u3044\u308b\u5834\u5408\u306f\u3001\u6b21\u306e\u624b\u9806\u306b\u5f93\u3044\u307e\u3059\u3002https:\/\/learn.microsoft.com\/en-us\/exchange\/client-developer\/legacy-protocols\/how-to-authenticate-an-imap-pop-smtp-application-by-using-oauth<\/p>\n<p>\u30af\u30e9\u30a4\u30a2\u30f3\u30c8\u304c OAuth \u3092\u30b5\u30dd\u30fc\u30c8\u3057\u3066\u304a\u3089\u305a\u3001\u30af\u30e9\u30a4\u30a2\u30f3\u30c8\u9001\u4fe1\u3067\u306e\u57fa\u672c\u8a8d\u8a3c (SMTP AUTH) \u3092\u4f7f\u7528\u3059\u308b\u5fc5\u8981\u304c\u3042\u308b\u5834\u5408\u306f\u30012026 \u5e74 4 \u6708\u4ee5\u524d\u3001\u4ee5\u524d\u306f 2025 \u5e74 9 \u6708\u307e\u3067\u306b\u3001\u6b21\u306e\u3044\u305a\u308c\u304b\u306e\u4ee3\u66ff\u624b\u6bb5\u306b\u5207\u308a\u66ff\u3048\u308b\u5fc5\u8981\u304c\u3042\u308a\u307e\u3059\u3002<\/p>\n<ul>\n<li>\u30af\u30e9\u30a4\u30a2\u30f3\u30c8\u9001\u4fe1 (SMTP AUTH) \u3067\u57fa\u672c\u8a8d\u8a3c\u3092\u4f7f\u7528\u3057\u3066\u3001\u30c6\u30ca\u30f3\u30c8\u5185\u306e\u53d7\u4fe1\u8005\u306b\u96fb\u5b50\u30e1\u30fc\u30eb\u3092\u9001\u4fe1\u3057\u3066\u3044\u308b\u5834\u5408\u306f\u3001Microsoft 365 \u5927\u5bb9\u91cf\u96fb\u5b50\u30e1\u30fc\u30eb\u3092\u4f7f\u7528\u3067\u304d\u307e\u3059\u3002\u8a73\u7d30\u306b\u3064\u3044\u3066\u306f\u3001\u3053\u306e\u30b5\u30a4\u30c8\u306b\u30a2\u30af\u30bb\u30b9\u3057\u3066\u304f\u3060\u3055\u3044:  <a href=\"https:\/\/learn.microsoft.com\/en-us\/Exchange\/mail-flow-best-practices\/high-volume-mails-m365\" target=\"_blank\">  Microsoft 365 \u30d1\u30d6\u30ea\u30c3\u30af \u30d7\u30ec\u30d3\u30e5\u30fc\u306e\u5927\u91cf\u306e\u30e1\u30fc\u30eb\u3092\u7ba1\u7406\u3059\u308b<\/a>  <\/li>\n<li>\u30cf\u30a4\u30d6\u30ea\u30c3\u30c9\u69cb\u6210\u3067\u30aa\u30f3\u30d7\u30ec\u30df\u30b9\u306e Exchange Server \u304c\u3042\u308b\u5834\u5408\u306f\u3001\u57fa\u672c\u8a8d\u8a3c\u3092\u4f7f\u7528\u3057\u3066\u30aa\u30f3\u30d7\u30ec\u30df\u30b9\u306e Exchange Server \u3067\u8a8d\u8a3c\u3059\u308b\u304b\u3001Exchange \u30b5\u30fc\u30d0\u30fc\u3067\u306e\u533f\u540d\u30ea\u30ec\u30fc\u3092\u8a31\u53ef\u3059\u308b\u53d7\u4fe1\u30b3\u30cd\u30af\u30bf\u3092\u4f7f\u7528\u3057\u3066\u30aa\u30f3\u30d7\u30ec\u30df\u30b9\u306e Exchange Server \u3092\u69cb\u6210\u3067\u304d\u307e\u3059\u3002\u8a73\u7d30\u306b\u3064\u3044\u3066\u306f\u3001\u3053\u306e\u30b5\u30a4\u30c8\u306b\u30a2\u30af\u30bb\u30b9\u3057\u3066\u304f\u3060\u3055\u3044:  <a href=\"https:\/\/learn.microsoft.com\/en-us\/exchange\/mail-flow\/connectors\/allow-anonymous-relay?view=exchserver-2019\" target=\"_blank\">  Exchange \u30b5\u30fc\u30d0\u30fc\u3067\u306e\u533f\u540d\u30ea\u30ec\u30fc\u306e\u8a31\u53ef<\/a>  <\/li>\n<\/ul>\n<p>\u96fb\u5b50\u30e1\u30fc\u30eb\u306e\u91cf\u306b\u95a2\u4fc2\u306a\u304f\u3001\u57fa\u672c\u8a8d\u8a3c\u3092\u4f7f\u7528\u3057\u3066 Exchange Online \u3067\u96fb\u5b50\u30e1\u30fc\u30eb\u3092\u9001\u4fe1\u3059\u308b\u5fc5\u8981\u304c\u3042\u308b\u5834\u5408\u306f\u3001\u4ee3\u66ff\u624b\u6bb5\u307e\u305f\u306f \u30bd\u30ea\u30e5\u30fc\u30b7\u30e7\u30f3\u306e\u3044\u305a\u308c\u304b\u3092\u4f7f\u7528\u3059\u308b\u5fc5\u8981\u304c\u3042\u308a\u307e\u3059\u3002<\/p>\n<p>\u3053\u306e\u5909\u66f4\u306b\u306f\u591a\u5c11\u306e\u8abf\u6574\u304c\u5fc5\u8981\u3067\u3042\u308b\u3053\u3068\u3092\u7406\u89e3\u3057\u3066\u3044\u307e\u3059\u304c\u3001\u3053\u308c\u306f\u5f53\u793e\u306e\u96fb\u5b50\u30e1\u30fc\u30eb \u30b5\u30fc\u30d3\u30b9\u3068\u304a\u5ba2\u69d8\u306e\u30c7\u30fc\u30bf\u306e\u30bb\u30ad\u30e5\u30ea\u30c6\u30a3\u3068\u4fe1\u983c\u6027\u3092\u5f37\u5316\u3059\u308b\u305f\u3081\u306b\u5fc5\u8981\u306a\u30b9\u30c6\u30c3\u30d7\u3067\u3042\u308b\u3068\u8003\u3048\u3066\u3044\u307e\u3059\u3002<\/p>\n<p>  <\/p>\n<p>  <\/p>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table><\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>MC1185464 | Usage Detected &#8211; Basic Auth with SMTP AUTH Classification preventOrFixIssue Last Updated 11\/ [&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-13768","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/posts\/13768","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=13768"}],"version-history":[{"count":0,"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/posts\/13768\/revisions"}],"wp:attachment":[{"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/media?parent=13768"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/categories?post=13768"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/tags?post=13768"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}