{"id":9501,"date":"2026-03-23T23:17:49","date_gmt":"2026-03-23T23:17:49","guid":{"rendered":"https:\/\/pariswells.com\/blog\/?p=9501"},"modified":"2026-03-25T21:58:32","modified_gmt":"2026-03-25T21:58:32","slug":"excessive-number-of-failed-connections-from-127-0-0-1-2","status":"publish","type":"post","link":"https:\/\/pariswells.com\/blog\/research\/excessive-number-of-failed-connections-from-127-0-0-1-2","title":{"rendered":"Excessive number of failed connections from 127.0.0.1"},"content":{"rendered":"\n<p>This Senitel Rule wasn&#8217;t the clearest with what was causing these<\/p>\n\n\n\n<p>I updated the rule to the below and also whitelisted some false positives <\/p>\n\n\n\n<pre class=\"wp-block-code\"><code class=\"\">DeviceNetworkEvents\n| where ActionType == \"ConnectionFailed\"\n\/\/ Rename LocalIP to SrcIpAddr early so it flows through to final output\n| extend SrcIpAddr = LocalIP\n| summarize Count = count() by \n    DeviceName,\n    DeviceId,\n    SrcIpAddr,\n    InitiatingProcessFileName,\n    InitiatingProcessCommandLine,\n    bin(Timestamp, 5m)\n| where Count > 100\n| summarize \n    TotalCount = sum(Count),\n    FirstSeen = min(Timestamp),\n    LastSeen = max(Timestamp)\n    by\n    DeviceName,\n    DeviceId,\n    SrcIpAddr,\n    InitiatingProcessFileName,\n    InitiatingProcessCommandLine\n| extend threshold = 5000\n| order by TotalCount desc<\/code><\/pre>\n\n\n\n<p>## Then Fix the Wizard Settings **Entity Mapping:** | Field | Value | |&#8212;|&#8212;| | Entity type | IP | | Identifier | Address | | Column | `SrcIpAddr` ? | **Custom Details:** | Key | Value | |&#8212;|&#8212;| | NumberOfDenies | `TotalCount` ? | **Alert Name Format:** &#8220;` Excessive number of failed connections from {{SrcIpAddr}} &#8220;` **Alert Description Format:** &#8220;` The client at address {{SrcIpAddr}} generated more than {{threshold}} failures over a 5 minutes time window, which may indicate malicious activity.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>This Senitel Rule wasn&#8217;t the clearest with what was causing these I updated the rule to the below and also whitelisted some false positives ## Then Fix [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-9501","post","type-post","status-publish","format-standard","hentry","category-research"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/pariswells.com\/blog\/wp-json\/wp\/v2\/posts\/9501","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pariswells.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/pariswells.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/pariswells.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/pariswells.com\/blog\/wp-json\/wp\/v2\/comments?post=9501"}],"version-history":[{"count":3,"href":"https:\/\/pariswells.com\/blog\/wp-json\/wp\/v2\/posts\/9501\/revisions"}],"predecessor-version":[{"id":9505,"href":"https:\/\/pariswells.com\/blog\/wp-json\/wp\/v2\/posts\/9501\/revisions\/9505"}],"wp:attachment":[{"href":"https:\/\/pariswells.com\/blog\/wp-json\/wp\/v2\/media?parent=9501"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/pariswells.com\/blog\/wp-json\/wp\/v2\/categories?post=9501"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/pariswells.com\/blog\/wp-json\/wp\/v2\/tags?post=9501"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}