S3 bucket suspicious ransomware activity
Id | b442b9e2-5cc4-4129-a85b-a5ef38a9e5f0 |
Rulename | S3 bucket suspicious ransomware activity |
Description | Suspicious S3 bucket activity indicating ransomware was detected. An attacker might download all the objects in a compromised S3 bucket, encrypt them with his own key, then upload them back to the same bucket, overwriting the existing ones. |
Severity | High |
Tactics | Impact |
Techniques | T1486 |
Required data connectors | AWS |
Kind | Scheduled |
Query frequency | 1h |
Query period | 1h |
Trigger threshold | 0 |
Trigger operator | gt |
Source Uri | https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Amazon Web Services/Analytic Rules/AWS_S3Ransomware.yaml |
Version | 1.0.1 |
Arm template | b442b9e2-5cc4-4129-a85b-a5ef38a9e5f0.json |
let timeframe = 1h;
let lookback = 2h;
// The attacker downloads the object(s) from the compromised bucket
let GetObject = AWSCloudTrail
| where TimeGenerated >= ago(lookback)
| where EventName == "GetObject" and isempty(ErrorCode) and isempty(ErrorMessage)
| extend bucketName = tostring(parse_json(RequestParameters).bucketName), keyName = tostring(parse_json(RequestParameters).key)
| project-rename StartTime = TimeGenerated;
// Then, the attacker overwrites the same object(s) but encrypted with his own key
let PutObject = AWSCloudTrail
| where TimeGenerated >= ago(timeframe)
| where EventName == "PutObject" and isempty(ErrorCode) and isempty(ErrorMessage)
| extend bucketName = tostring(parse_json(RequestParameters).bucketName), keyName = tostring(parse_json(RequestParameters).key)
| extend kmsId = tostring(parse_json(RequestParameters).["x-amz-server-side-encryption-aws-kms-key-id"])
| where tostring(kmsId) !has tostring(RecipientAccountId) and kmsId <> "";
PutObject
| join kind=inner
(
GetObject
)
on $left.bucketName == $right.bucketName, $left.keyName == $right.keyName
| where TimeGenerated > StartTime
| extend UserIdentityArn = iif(isempty(UserIdentityArn), tostring(parse_json(Resources)[0].ARN), UserIdentityArn)
| extend UserName = tostring(split(UserIdentityArn, '/')[-1])
| extend AccountName = case( UserIdentityPrincipalid == "Anonymous", "Anonymous", isempty(UserIdentityUserName), UserName, UserIdentityUserName)
| extend AccountName = iif(AccountName contains "@", tostring(split(AccountName, '@', 0)[0]), AccountName),
AccountUPNSuffix = iif(AccountName contains "@", tostring(split(AccountName, '@', 1)[0]), "")
| extend timestamp = StartTime
queryPeriod: 1h
version: 1.0.1
tactics:
- Impact
queryFrequency: 1h
id: b442b9e2-5cc4-4129-a85b-a5ef38a9e5f0
triggerOperator: gt
requiredDataConnectors:
- dataTypes:
- AWSCloudTrail
connectorId: AWS
severity: High
entityMappings:
- entityType: Account
fieldMappings:
- columnName: AccountName
identifier: Name
- columnName: AccountUPNSuffix
identifier: UPNSuffix
- columnName: RecipientAccountId
identifier: CloudAppAccountId
- entityType: IP
fieldMappings:
- columnName: SourceIpAddress
identifier: Address
triggerThreshold: 0
relevantTechniques:
- T1486
query: |
let timeframe = 1h;
let lookback = 2h;
// The attacker downloads the object(s) from the compromised bucket
let GetObject = AWSCloudTrail
| where TimeGenerated >= ago(lookback)
| where EventName == "GetObject" and isempty(ErrorCode) and isempty(ErrorMessage)
| extend bucketName = tostring(parse_json(RequestParameters).bucketName), keyName = tostring(parse_json(RequestParameters).key)
| project-rename StartTime = TimeGenerated;
// Then, the attacker overwrites the same object(s) but encrypted with his own key
let PutObject = AWSCloudTrail
| where TimeGenerated >= ago(timeframe)
| where EventName == "PutObject" and isempty(ErrorCode) and isempty(ErrorMessage)
| extend bucketName = tostring(parse_json(RequestParameters).bucketName), keyName = tostring(parse_json(RequestParameters).key)
| extend kmsId = tostring(parse_json(RequestParameters).["x-amz-server-side-encryption-aws-kms-key-id"])
| where tostring(kmsId) !has tostring(RecipientAccountId) and kmsId <> "";
PutObject
| join kind=inner
(
GetObject
)
on $left.bucketName == $right.bucketName, $left.keyName == $right.keyName
| where TimeGenerated > StartTime
| extend UserIdentityArn = iif(isempty(UserIdentityArn), tostring(parse_json(Resources)[0].ARN), UserIdentityArn)
| extend UserName = tostring(split(UserIdentityArn, '/')[-1])
| extend AccountName = case( UserIdentityPrincipalid == "Anonymous", "Anonymous", isempty(UserIdentityUserName), UserName, UserIdentityUserName)
| extend AccountName = iif(AccountName contains "@", tostring(split(AccountName, '@', 0)[0]), AccountName),
AccountUPNSuffix = iif(AccountName contains "@", tostring(split(AccountName, '@', 1)[0]), "")
| extend timestamp = StartTime
kind: Scheduled
name: S3 bucket suspicious ransomware activity
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Amazon Web Services/Analytic Rules/AWS_S3Ransomware.yaml
description: |
'Suspicious S3 bucket activity indicating ransomware was detected.
An attacker might download all the objects in a compromised S3 bucket, encrypt them with his own key, then upload them back to the same bucket, overwriting the existing ones.'
status: Available
{
"$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/b442b9e2-5cc4-4129-a85b-a5ef38a9e5f0')]",
"kind": "Scheduled",
"name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/b442b9e2-5cc4-4129-a85b-a5ef38a9e5f0')]",
"properties": {
"alertRuleTemplateName": "b442b9e2-5cc4-4129-a85b-a5ef38a9e5f0",
"customDetails": null,
"description": "'Suspicious S3 bucket activity indicating ransomware was detected.\nAn attacker might download all the objects in a compromised S3 bucket, encrypt them with his own key, then upload them back to the same bucket, overwriting the existing ones.'\n",
"displayName": "S3 bucket suspicious ransomware activity",
"enabled": true,
"entityMappings": [
{
"entityType": "Account",
"fieldMappings": [
{
"columnName": "AccountName",
"identifier": "Name"
},
{
"columnName": "AccountUPNSuffix",
"identifier": "UPNSuffix"
},
{
"columnName": "RecipientAccountId",
"identifier": "CloudAppAccountId"
}
]
},
{
"entityType": "IP",
"fieldMappings": [
{
"columnName": "SourceIpAddress",
"identifier": "Address"
}
]
}
],
"OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Amazon Web Services/Analytic Rules/AWS_S3Ransomware.yaml",
"query": "let timeframe = 1h;\nlet lookback = 2h;\n// The attacker downloads the object(s) from the compromised bucket\nlet GetObject = AWSCloudTrail\n| where TimeGenerated >= ago(lookback)\n| where EventName == \"GetObject\" and isempty(ErrorCode) and isempty(ErrorMessage)\n| extend bucketName = tostring(parse_json(RequestParameters).bucketName), keyName = tostring(parse_json(RequestParameters).key)\n| project-rename StartTime = TimeGenerated;\n// Then, the attacker overwrites the same object(s) but encrypted with his own key\nlet PutObject = AWSCloudTrail\n| where TimeGenerated >= ago(timeframe)\n| where EventName == \"PutObject\" and isempty(ErrorCode) and isempty(ErrorMessage)\n| extend bucketName = tostring(parse_json(RequestParameters).bucketName), keyName = tostring(parse_json(RequestParameters).key)\n| extend kmsId = tostring(parse_json(RequestParameters).[\"x-amz-server-side-encryption-aws-kms-key-id\"])\n| where tostring(kmsId) !has tostring(RecipientAccountId) and kmsId <> \"\";\nPutObject\n| join kind=inner \n(\n GetObject\n)\non $left.bucketName == $right.bucketName, $left.keyName == $right.keyName\n| where TimeGenerated > StartTime\n| extend UserIdentityArn = iif(isempty(UserIdentityArn), tostring(parse_json(Resources)[0].ARN), UserIdentityArn)\n| extend UserName = tostring(split(UserIdentityArn, '/')[-1])\n| extend AccountName = case( UserIdentityPrincipalid == \"Anonymous\", \"Anonymous\", isempty(UserIdentityUserName), UserName, UserIdentityUserName)\n| extend AccountName = iif(AccountName contains \"@\", tostring(split(AccountName, '@', 0)[0]), AccountName),\n AccountUPNSuffix = iif(AccountName contains \"@\", tostring(split(AccountName, '@', 1)[0]), \"\")\n| extend timestamp = StartTime\n",
"queryFrequency": "PT1H",
"queryPeriod": "PT1H",
"severity": "High",
"status": "Available",
"subTechniques": [],
"suppressionDuration": "PT1H",
"suppressionEnabled": false,
"tactics": [
"Impact"
],
"techniques": [
"T1486"
],
"templateVersion": "1.0.1",
"triggerOperator": "GreaterThan",
"triggerThreshold": 0
},
"type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
}
]
}