AWS CloudWatch Log Group Deletion

Identifies the deletion of a specified AWS CloudWatch log group. When a log group is deleted, all the archived log events associated with the log group are also permanently deleted.

Elastic rule (View on GitHub)

  1[metadata]
  2creation_date = "2020/05/18"
  3integration = ["aws"]
  4maturity = "production"
  5min_stack_comments = "AWS integration breaking changes, bumping version to ^2.0.0"
  6min_stack_version = "8.9.0"
  7updated_date = "2023/10/24"
  8
  9[rule]
 10author = ["Elastic"]
 11description = """
 12Identifies the deletion of a specified AWS CloudWatch log group. When a log group is deleted, all the archived log
 13events associated with the log group are also permanently deleted.
 14"""
 15false_positives = [
 16    """
 17    Verify whether the user identity, user agent, and/or hostname should be making changes in your environment. Log
 18    group deletions by unfamiliar users or hosts should be investigated. If known behavior is causing false positives,
 19    it can be exempted from the rule.
 20    """,
 21]
 22from = "now-60m"
 23index = ["filebeat-*", "logs-aws*"]
 24interval = "10m"
 25language = "kuery"
 26license = "Elastic License v2"
 27name = "AWS CloudWatch Log Group Deletion"
 28note = """## Triage and analysis
 29
 30### Investigating AWS CloudWatch Log Group Deletion
 31
 32Amazon CloudWatch is a monitoring and observability service that collects monitoring and operational data in the form of logs, metrics, and events for resources and applications. This data can be used to detect anomalous behavior in your environments, set alarms, visualize logs and metrics side by side, take automated actions, troubleshoot issues, and discover insights to keep your applications running smoothly.
 33
 34A log group is a group of log streams that share the same retention, monitoring, and access control settings. You can define log groups and specify which streams to put into each group. There is no limit on the number of log streams that can belong to one log group.
 35
 36This rule looks for the deletion of a log group using the API `DeleteLogGroup` action. Attackers can do this to cover their tracks and impact security monitoring that relies on these sources.
 37
 38#### Possible investigation steps
 39
 40- Identify the user account that performed the action and whether it should perform this kind of action.
 41- Investigate other alerts associated with the user account during the past 48 hours.
 42- Contact the account and resource owners and confirm whether they are aware of this activity.
 43- Check if this operation was approved and performed according to the organization's change management policy.
 44- Considering the source IP address and geolocation of the user who issued the command:
 45    - Do they look normal for the user?
 46    - If the source is an EC2 IP address, is it associated with an EC2 instance in one of your accounts or is the source IP from an EC2 instance that's not under your control?
 47    - If it is an authorized EC2 instance, is the activity associated with normal behavior for the instance role or roles? Are there any other alerts or signs of suspicious activity involving this instance?
 48- Investigate the deleted log group's criticality and whether the responsible team is aware of the deletion.
 49- If you suspect the account has been compromised, scope potentially compromised assets by tracking servers, services, and data accessed by the account in the last 24 hours.
 50
 51### False positive analysis
 52
 53- If this rule is noisy in your environment due to expected activity, consider adding exceptions — preferably with a combination of user and IP address conditions.
 54
 55### Response and remediation
 56
 57- Initiate the incident response process based on the outcome of the triage.
 58- Disable or limit the account during the investigation and response.
 59- Identify the possible impact of the incident and prioritize accordingly; the following actions can help you gain context:
 60    - Identify the account role in the cloud environment.
 61    - Assess the criticality of affected services and servers.
 62    - Work with your IT team to identify and minimize the impact on users.
 63    - Identify if the attacker is moving laterally and compromising other accounts, servers, or services.
 64    - Identify any regulatory or legal ramifications related to this activity.
 65- Investigate credential exposure on systems compromised or used by the attacker to ensure all compromised accounts are identified. Reset passwords or delete API keys as needed to revoke the attacker's access to the environment. Work with your IT teams to minimize the impact on business operations during these actions.
 66- Check if unauthorized new users were created, remove unauthorized new accounts, and request password resets for other IAM users.
 67- Consider enabling multi-factor authentication for users.
 68- Review the permissions assigned to the implicated user to ensure that the least privilege principle is being followed.
 69- Implement security best practices [outlined](https://aws.amazon.com/premiumsupport/knowledge-center/security-best-practices/) by AWS.
 70- Take the actions needed to return affected systems, data, or services to their normal operational levels.
 71- Identify the initial vector abused by the attacker and take action to prevent reinfection via the same vector.
 72- Using the incident response data, update logging and audit policies to improve the mean time to detect (MTTD) and the mean time to respond (MTTR).
 73
 74## Setup
 75
 76The AWS Fleet integration, Filebeat module, or similarly structured data is required to be compatible with this rule."""
 77references = [
 78    "https://awscli.amazonaws.com/v2/documentation/api/latest/reference/logs/delete-log-group.html",
 79    "https://docs.aws.amazon.com/AmazonCloudWatchLogs/latest/APIReference/API_DeleteLogGroup.html",
 80]
 81risk_score = 47
 82rule_id = "68a7a5a5-a2fc-4a76-ba9f-26849de881b4"
 83severity = "medium"
 84tags = ["Domain: Cloud", "Data Source: AWS", "Data Source: Amazon Web Services", "Use Case: Log Auditing", "Resources: Investigation Guide", "Tactic: Impact"]
 85timestamp_override = "event.ingested"
 86type = "query"
 87
 88query = '''
 89event.dataset:aws.cloudtrail and event.provider:logs.amazonaws.com and event.action:DeleteLogGroup and event.outcome:success
 90'''
 91
 92
 93[[rule.threat]]
 94framework = "MITRE ATT&CK"
 95[[rule.threat.technique]]
 96id = "T1485"
 97name = "Data Destruction"
 98reference = "https://attack.mitre.org/techniques/T1485/"
 99
100
101[rule.threat.tactic]
102id = "TA0040"
103name = "Impact"
104reference = "https://attack.mitre.org/tactics/TA0040/"
105[[rule.threat]]
106framework = "MITRE ATT&CK"
107[[rule.threat.technique]]
108id = "T1562"
109name = "Impair Defenses"
110reference = "https://attack.mitre.org/techniques/T1562/"
111[[rule.threat.technique.subtechnique]]
112id = "T1562.001"
113name = "Disable or Modify Tools"
114reference = "https://attack.mitre.org/techniques/T1562/001/"
115
116
117
118[rule.threat.tactic]
119id = "TA0005"
120name = "Defense Evasion"
121reference = "https://attack.mitre.org/tactics/TA0005/"

Triage and analysis

Investigating AWS CloudWatch Log Group Deletion

Amazon CloudWatch is a monitoring and observability service that collects monitoring and operational data in the form of logs, metrics, and events for resources and applications. This data can be used to detect anomalous behavior in your environments, set alarms, visualize logs and metrics side by side, take automated actions, troubleshoot issues, and discover insights to keep your applications running smoothly.

A log group is a group of log streams that share the same retention, monitoring, and access control settings. You can define log groups and specify which streams to put into each group. There is no limit on the number of log streams that can belong to one log group.

This rule looks for the deletion of a log group using the API DeleteLogGroup action. Attackers can do this to cover their tracks and impact security monitoring that relies on these sources.

Possible investigation steps

  • Identify the user account that performed the action and whether it should perform this kind of action.
  • Investigate other alerts associated with the user account during the past 48 hours.
  • Contact the account and resource owners and confirm whether they are aware of this activity.
  • Check if this operation was approved and performed according to the organization's change management policy.
  • Considering the source IP address and geolocation of the user who issued the command:
    • Do they look normal for the user?
    • If the source is an EC2 IP address, is it associated with an EC2 instance in one of your accounts or is the source IP from an EC2 instance that's not under your control?
    • If it is an authorized EC2 instance, is the activity associated with normal behavior for the instance role or roles? Are there any other alerts or signs of suspicious activity involving this instance?
  • Investigate the deleted log group's criticality and whether the responsible team is aware of the deletion.
  • If you suspect the account has been compromised, scope potentially compromised assets by tracking servers, services, and data accessed by the account in the last 24 hours.

False positive analysis

  • If this rule is noisy in your environment due to expected activity, consider adding exceptions — preferably with a combination of user and IP address conditions.

Response and remediation

  • Initiate the incident response process based on the outcome of the triage.
  • Disable or limit the account during the investigation and response.
  • Identify the possible impact of the incident and prioritize accordingly; the following actions can help you gain context:
    • Identify the account role in the cloud environment.
    • Assess the criticality of affected services and servers.
    • Work with your IT team to identify and minimize the impact on users.
    • Identify if the attacker is moving laterally and compromising other accounts, servers, or services.
    • Identify any regulatory or legal ramifications related to this activity.
  • Investigate credential exposure on systems compromised or used by the attacker to ensure all compromised accounts are identified. Reset passwords or delete API keys as needed to revoke the attacker's access to the environment. Work with your IT teams to minimize the impact on business operations during these actions.
  • Check if unauthorized new users were created, remove unauthorized new accounts, and request password resets for other IAM users.
  • Consider enabling multi-factor authentication for users.
  • Review the permissions assigned to the implicated user to ensure that the least privilege principle is being followed.
  • Implement security best practices outlined by AWS.
  • Take the actions needed to return affected systems, data, or services to their normal operational levels.
  • Identify the initial vector abused by the attacker and take action to prevent reinfection via the same vector.
  • Using the incident response data, update logging and audit policies to improve the mean time to detect (MTTD) and the mean time to respond (MTTR).

Setup

The AWS Fleet integration, Filebeat module, or similarly structured data is required to be compatible with this rule.

References

Related rules

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