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alibabacloud

A log monitoring and alerts is set up for OSS bucket policy changes

sls_oss_bucket_policy_changes_alert_enabled
Service: slsSeverity: medium
OfficialBuilt-inVerified
Categories:logging
Resource Type:ALIYUN::SLS::Alert

Alibaba Cloud SLS should have an alarm configured for OSS bucket policy changes. By directing ActionTrail logs to SLS with alert rules, modifications to bucket access policies are detected promptly, enabling quick identification of dangerous permission changes on sensitive storage resources.

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Risk

Without monitoring for OSS bucket policy changes, malicious modifications may go undetected, leading to unintended data exposure. Unauthorized users could access or delete sensitive objects. Delayed detection increases risk of data breaches, data exfiltration, and compliance violations as attackers silently widen access to storage resources.

Run this check with Prowler

Run in Prowler Cloud
Run
prowler alibabacloud --checks sls_oss_bucket_policy_changes_alert_enabled

Recommendation

  1. Log on to the SLS Console
  2. Ensure ActionTrail is enabled
  3. Select Alerts
  4. Ensure alert rule has been enabled for OSS bucket policy changes

Remediation

CLI

aliyun sls create-alert --project <project-name> --alert-name oss-bucket-policy-changes --alert-displayname 'OSS Bucket Policy Changes Alert' --condition 'event.serviceName: Oss and (event.eventName: PutBucketPolicy or event.eventName: DeleteBucketPolicy)' --dashboard <dashboard-name> --schedule '{"type":"FixedRate","interval":"1m"}'

Other

1Log on to the **SLS Console**.
2Ensure **ActionTrail** is enabled and delivering logs to a **Log Service** project.
3Navigate to the project receiving ActionTrail logs.
4Select **Alerts** and click **Create Alert Rule**.
5Configure the query to filter for OSS bucket policy changes: `event.serviceName: Oss and (event.eventName: PutBucketPolicy or event.eventName: DeleteBucketPolicy)`.
6Set the alert **schedule**, **notification method**, and **severity**.
7Save and enable the alert rule.

Check Code

from prowler.lib.check.models import Check, CheckReportAlibabaCloud
from prowler.providers.alibabacloud.services.sls.sls_client import sls_client


class sls_oss_bucket_policy_changes_alert_enabled(Check):
    def execute(self) -> list[CheckReportAlibabaCloud]:
        findings = []
        found = False

        for alert in sls_client.alerts:
            query_list = alert.configuration.get("queryList", [])
            if not query_list:
                continue

            for query_obj in query_list:
                query = query_obj.get("query", "")
                if (
                    "PutBucketLifecycle" in query
                    or "PutBucketPolicy" in query
                    or "PutBucketCors" in query
                    or "PutBucketEncryption" in query
                    or "PutBucketReplication" in query
                    or "DeleteBucketPolicy" in query
                    or "DeleteBucketCors" in query
                    or "DeleteBucketLifecycle" in query
                    or "DeleteBucketEncryption" in query
                    or "DeleteBucketReplication" in query
                ):
                    found = True
                    report = CheckReportAlibabaCloud(
                        metadata=self.metadata(), resource=alert
                    )
                    report.status = "PASS"
                    report.status_extended = f"SLS Alert {alert.name} is configured for OSS bucket policy changes."
                    report.resource_id = alert.name
                    report.resource_arn = alert.arn
                    report.region = alert.region
                    findings.append(report)
                    break

            if found:
                break

        if not found:
            report = CheckReportAlibabaCloud(
                metadata=self.metadata(), resource=sls_client.provider.identity
            )
            report.status = "FAIL"
            report.status_extended = (
                "No SLS Alert configured for OSS bucket policy changes."
            )
            report.resource_id = sls_client.audited_account
            report.resource_arn = sls_client.provider.identity.identity_arn
            report.region = sls_client.region
            findings.append(report)

        return findings

References