let LearningPeriod = 7d;
let BinTime = 1h;
let RunTime = 1h;
let StartTime = 1h;
let NumberOfStds = 3;
let MinThreshold = 10.0;
let EndRunTime = StartTime - RunTime;
let EndLearningTime = StartTime + LearningPeriod;
let GitLabRepositoryDestroyEvents = (GitLabAudit
| where RemoveAction == "project" or RemoveAction == "repository");
GitLabRepositoryDestroyEvents
| where TimeGenerated between (ago(EndLearningTime) .. ago(StartTime))
| summarize count() by bin(TimeGenerated, BinTime)
| summarize AvgInLearning = avg(count_), StdInLearning = stdev(count_)
| extend LearningThreshold = max_of(AvgInLearning + StdInLearning * NumberOfStds, MinThreshold)
| extend Dummy = 1
| join kind=innerunique (GitLabRepositoryDestroyEvents
| where TimeGenerated between (ago(StartTime) .. ago(EndRunTime))
| summarize CountInRunTime = count() by bin(TimeGenerated, BinTime)
| extend Dummy = 1) on Dummy
| project-away Dummy
| where CountInRunTime > LearningThreshold
id: 3efd09bd-a582-4410-b7ec-5ff21cfad7bd
triggerOperator: gt
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/GitLab/Analytic Rules/GitLab_Repo_Deletion.yaml
requiredDataConnectors:
- dataTypes:
- Syslog
connectorId: Syslog
description: |
'This hunting queries identify an unusual increase of repo deletion activities adversaries may want to disrupt availability or compromise integrity by deleting business data.'
severity: Medium
queryPeriod: 1d
kind: Scheduled
tactics:
- Impact
queryFrequency: 1h
query: |
let LearningPeriod = 7d;
let BinTime = 1h;
let RunTime = 1h;
let StartTime = 1h;
let NumberOfStds = 3;
let MinThreshold = 10.0;
let EndRunTime = StartTime - RunTime;
let EndLearningTime = StartTime + LearningPeriod;
let GitLabRepositoryDestroyEvents = (GitLabAudit
| where RemoveAction == "project" or RemoveAction == "repository");
GitLabRepositoryDestroyEvents
| where TimeGenerated between (ago(EndLearningTime) .. ago(StartTime))
| summarize count() by bin(TimeGenerated, BinTime)
| summarize AvgInLearning = avg(count_), StdInLearning = stdev(count_)
| extend LearningThreshold = max_of(AvgInLearning + StdInLearning * NumberOfStds, MinThreshold)
| extend Dummy = 1
| join kind=innerunique (GitLabRepositoryDestroyEvents
| where TimeGenerated between (ago(StartTime) .. ago(EndRunTime))
| summarize CountInRunTime = count() by bin(TimeGenerated, BinTime)
| extend Dummy = 1) on Dummy
| project-away Dummy
| where CountInRunTime > LearningThreshold
version: 1.0.0
triggerThreshold: 0
name: GitLab - Abnormal number of repositories deleted
entityMappings:
- entityType: IP
fieldMappings:
- columnName: IPAddress
identifier: Address
- entityType: Account
fieldMappings:
- columnName: AuthorName
identifier: FullName
status: Available
relevantTechniques:
- T1485
{
"$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
"contentVersion": "1.0.0.0",
"parameters": {
"workspace": {
"type": "String"
}
},
"resources": [
{
"apiVersion": "2024-01-01-preview",
"id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/3efd09bd-a582-4410-b7ec-5ff21cfad7bd')]",
"kind": "Scheduled",
"name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/3efd09bd-a582-4410-b7ec-5ff21cfad7bd')]",
"properties": {
"alertRuleTemplateName": "3efd09bd-a582-4410-b7ec-5ff21cfad7bd",
"customDetails": null,
"description": "'This hunting queries identify an unusual increase of repo deletion activities adversaries may want to disrupt availability or compromise integrity by deleting business data.'\n",
"displayName": "GitLab - Abnormal number of repositories deleted",
"enabled": true,
"entityMappings": [
{
"entityType": "IP",
"fieldMappings": [
{
"columnName": "IPAddress",
"identifier": "Address"
}
]
},
{
"entityType": "Account",
"fieldMappings": [
{
"columnName": "AuthorName",
"identifier": "FullName"
}
]
}
],
"OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/GitLab/Analytic Rules/GitLab_Repo_Deletion.yaml",
"query": "let LearningPeriod = 7d;\nlet BinTime = 1h;\nlet RunTime = 1h;\nlet StartTime = 1h;\nlet NumberOfStds = 3;\nlet MinThreshold = 10.0;\nlet EndRunTime = StartTime - RunTime;\nlet EndLearningTime = StartTime + LearningPeriod;\nlet GitLabRepositoryDestroyEvents = (GitLabAudit\n| where RemoveAction == \"project\" or RemoveAction == \"repository\");\nGitLabRepositoryDestroyEvents\n| where TimeGenerated between (ago(EndLearningTime) .. ago(StartTime))\n| summarize count() by bin(TimeGenerated, BinTime)\n| summarize AvgInLearning = avg(count_), StdInLearning = stdev(count_)\n| extend LearningThreshold = max_of(AvgInLearning + StdInLearning * NumberOfStds, MinThreshold)\n| extend Dummy = 1\n| join kind=innerunique (GitLabRepositoryDestroyEvents\n| where TimeGenerated between (ago(StartTime) .. ago(EndRunTime))\n| summarize CountInRunTime = count() by bin(TimeGenerated, BinTime)\n| extend Dummy = 1) on Dummy\n| project-away Dummy\n| where CountInRunTime > LearningThreshold\n",
"queryFrequency": "PT1H",
"queryPeriod": "P1D",
"severity": "Medium",
"status": "Available",
"subTechniques": [],
"suppressionDuration": "PT1H",
"suppressionEnabled": false,
"tactics": [
"Impact"
],
"techniques": [
"T1485"
],
"templateVersion": "1.0.0",
"triggerOperator": "GreaterThan",
"triggerThreshold": 0
},
"type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
}
]
}