Exchange SSRF Autodiscover ProxyShell - Detection
| Id | 968358d6-6af8-49bb-aaa4-187b3067fb95 |
| Rulename | Exchange SSRF Autodiscover ProxyShell - Detection |
| Description | This query looks for suspicious request patterns to Exchange servers that fit patterns recently blogged about by PeterJson. This exploitation chain utilises an SSRF vulnerability in Exchange which eventually allows the attacker to execute arbitrary Powershell on the server. In the example powershell can be used to write an email to disk with an encoded attachment containing a shell. Reference: https://peterjson.medium.com/reproducing-the-proxyshell-pwn2own-exploit-49743a4ea9a1 |
| Severity | High |
| Tactics | InitialAccess |
| Techniques | T1190 |
| Required data connectors | AzureMonitor(IIS) |
| Kind | Scheduled |
| Query frequency | 12h |
| Query period | 12h |
| Trigger threshold | 0 |
| Trigger operator | gt |
| Source Uri | https://github.com/Azure/Azure-Sentinel/blob/master/Detections/W3CIISLog/ProxyShellPwn2Own.yaml |
| Version | 1.0.3 |
| Arm template | 968358d6-6af8-49bb-aaa4-187b3067fb95.json |
let successCodes = dynamic([200, 302, 401]);
W3CIISLog
| where scStatus has_any (successCodes)
| where ipv4_is_private(cIP) == False
| where csUriStem hasprefix "/autodiscover/autodiscover.json"
| project TimeGenerated, cIP, sIP, sSiteName, csUriStem, csUriQuery, Computer, csUserName, _ResourceId, FileUri
| where (csUriQuery !has "Protocol" and isnotempty(csUriQuery))
or (csUriQuery has_any("/mapi/", "powershell"))
or (csUriQuery contains "@" and csUriQuery matches regex @"\.[a-zA-Z]{2,4}?(?:[a-zA-Z]{2,4}\/)")
or (csUriQuery contains ":" and csUriQuery matches regex @"\:[0-9]{2,4}\/")
| extend HostName = tostring(split(Computer, ".")[0]), DomainIndex = toint(indexof(Computer, '.'))
| extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)
| extend AccountName = tostring(split(csUserName, "@")[0]), AccountUPNSuffix = tostring(split(csUserName, "@")[1])
id: 968358d6-6af8-49bb-aaa4-187b3067fb95
tactics:
- InitialAccess
queryPeriod: 12h
metadata:
categories:
domains:
- Security - Others
source:
kind: Community
support:
tier: Community
author:
name: Thomas McElroy
triggerThreshold: 0
name: Exchange SSRF Autodiscover ProxyShell - Detection
query: |
let successCodes = dynamic([200, 302, 401]);
W3CIISLog
| where scStatus has_any (successCodes)
| where ipv4_is_private(cIP) == False
| where csUriStem hasprefix "/autodiscover/autodiscover.json"
| project TimeGenerated, cIP, sIP, sSiteName, csUriStem, csUriQuery, Computer, csUserName, _ResourceId, FileUri
| where (csUriQuery !has "Protocol" and isnotempty(csUriQuery))
or (csUriQuery has_any("/mapi/", "powershell"))
or (csUriQuery contains "@" and csUriQuery matches regex @"\.[a-zA-Z]{2,4}?(?:[a-zA-Z]{2,4}\/)")
or (csUriQuery contains ":" and csUriQuery matches regex @"\:[0-9]{2,4}\/")
| extend HostName = tostring(split(Computer, ".")[0]), DomainIndex = toint(indexof(Computer, '.'))
| extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)
| extend AccountName = tostring(split(csUserName, "@")[0]), AccountUPNSuffix = tostring(split(csUserName, "@")[1])
severity: High
triggerOperator: gt
kind: Scheduled
relevantTechniques:
- T1190
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Detections/W3CIISLog/ProxyShellPwn2Own.yaml
queryFrequency: 12h
requiredDataConnectors:
- connectorId: AzureMonitor(IIS)
dataTypes:
- W3CIISLog
description: |
'This query looks for suspicious request patterns to Exchange servers that fit patterns recently blogged about by PeterJson. This exploitation chain utilises an SSRF vulnerability in Exchange which eventually allows the attacker to execute arbitrary Powershell on the server.
In the example powershell can be used to write an email to disk with an encoded attachment containing a shell.
Reference: https://peterjson.medium.com/reproducing-the-proxyshell-pwn2own-exploit-49743a4ea9a1'
version: 1.0.3
entityMappings:
- fieldMappings:
- columnName: csUserName
identifier: FullName
- columnName: AccountName
identifier: Name
- columnName: AccountUPNSuffix
identifier: UPNSuffix
entityType: Account
- fieldMappings:
- columnName: Computer
identifier: FullName
entityType: Host
- fieldMappings:
- columnName: cIP
identifier: Address
entityType: IP
- fieldMappings:
- columnName: _ResourceId
identifier: ResourceId
entityType: AzureResource
{
"$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/968358d6-6af8-49bb-aaa4-187b3067fb95')]",
"kind": "Scheduled",
"name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/968358d6-6af8-49bb-aaa4-187b3067fb95')]",
"properties": {
"alertRuleTemplateName": "968358d6-6af8-49bb-aaa4-187b3067fb95",
"customDetails": null,
"description": "'This query looks for suspicious request patterns to Exchange servers that fit patterns recently blogged about by PeterJson. This exploitation chain utilises an SSRF vulnerability in Exchange which eventually allows the attacker to execute arbitrary Powershell on the server.\nIn the example powershell can be used to write an email to disk with an encoded attachment containing a shell.\nReference: https://peterjson.medium.com/reproducing-the-proxyshell-pwn2own-exploit-49743a4ea9a1'\n",
"displayName": "Exchange SSRF Autodiscover ProxyShell - Detection",
"enabled": true,
"entityMappings": [
{
"entityType": "Account",
"fieldMappings": [
{
"columnName": "csUserName",
"identifier": "FullName"
},
{
"columnName": "AccountName",
"identifier": "Name"
},
{
"columnName": "AccountUPNSuffix",
"identifier": "UPNSuffix"
}
]
},
{
"entityType": "Host",
"fieldMappings": [
{
"columnName": "Computer",
"identifier": "FullName"
}
]
},
{
"entityType": "IP",
"fieldMappings": [
{
"columnName": "cIP",
"identifier": "Address"
}
]
},
{
"entityType": "AzureResource",
"fieldMappings": [
{
"columnName": "_ResourceId",
"identifier": "ResourceId"
}
]
}
],
"OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Detections/W3CIISLog/ProxyShellPwn2Own.yaml",
"query": "let successCodes = dynamic([200, 302, 401]);\nW3CIISLog\n| where scStatus has_any (successCodes)\n| where ipv4_is_private(cIP) == False\n| where csUriStem hasprefix \"/autodiscover/autodiscover.json\"\n| project TimeGenerated, cIP, sIP, sSiteName, csUriStem, csUriQuery, Computer, csUserName, _ResourceId, FileUri\n| where (csUriQuery !has \"Protocol\" and isnotempty(csUriQuery))\nor (csUriQuery has_any(\"/mapi/\", \"powershell\"))\nor (csUriQuery contains \"@\" and csUriQuery matches regex @\"\\.[a-zA-Z]{2,4}?(?:[a-zA-Z]{2,4}\\/)\")\nor (csUriQuery contains \":\" and csUriQuery matches regex @\"\\:[0-9]{2,4}\\/\")\n| extend HostName = tostring(split(Computer, \".\")[0]), DomainIndex = toint(indexof(Computer, '.'))\n| extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)\n| extend AccountName = tostring(split(csUserName, \"@\")[0]), AccountUPNSuffix = tostring(split(csUserName, \"@\")[1])\n",
"queryFrequency": "PT12H",
"queryPeriod": "PT12H",
"severity": "High",
"subTechniques": [],
"suppressionDuration": "PT1H",
"suppressionEnabled": false,
"tactics": [
"InitialAccess"
],
"techniques": [
"T1190"
],
"templateVersion": "1.0.3",
"triggerOperator": "GreaterThan",
"triggerThreshold": 0
},
"type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
}
]
}