I reduced the history window for new terms rules that were either:
- `now-14 days`
- showing slow performance metrics
There are still several AWS rules with a `now-10d` window but they are not showing any performance issues so I'd like to leave them as is for now.
First Time Seen AWS Secret Value Accessed in Secrets Manager
- removed `BatchGetSecretValue` API call since this calls `GetSecretValue`
- removed the user_agent exclusions from this one, too easy to bypass.
AWS EC2 User Data Retrieval for EC2 Instance
- excluded more benign AWS services from telemetry
AWS IAM Assume Role Policy Update
- removed use of cloudformation exclusion, this should be captured as well
* [Tuning] Windows BruteForce Rules Tuning
#1 Multiple Logon Failure from the same Source Address: converted to ES|QL and raised the threshold to 100 failed auths, alert quality should be better since it aggregates all failed auths info into one alert vs multiple EQL matches. (expected reduction more than 50%)
#2 Privileged Account Brute Force - coverted to ESQL and set the threshold to 50 in a minute. this should drop noise volume by more than 50%.
* ++
* Update execution_shell_evasion_linux_binary.toml
* Update execution_shell_evasion_linux_binary.toml
* Update defense_evasion_indirect_exec_forfiles.toml
* Update lateral_movement_remote_file_copy_hidden_share.toml
* Update lateral_movement_remote_file_copy_hidden_share.toml
* Update persistence_service_windows_service_winlog.toml
* Update credential_access_lsass_openprocess_api.toml
* Update persistence_suspicious_scheduled_task_runtime.toml
* Update impact_hosts_file_modified.toml
* Update defense_evasion_process_termination_followed_by_deletion.toml
* Update rules/windows/credential_access_lsass_openprocess_api.toml
* Update rules/windows/credential_access_bruteforce_admin_account.toml
Co-authored-by: Ruben Groenewoud <78494512+Aegrah@users.noreply.github.com>
* Update rules/windows/credential_access_lsass_openprocess_api.toml
Co-authored-by: Ruben Groenewoud <78494512+Aegrah@users.noreply.github.com>
* Update rules/windows/credential_access_bruteforce_multiple_logon_failure_same_srcip.toml
Co-authored-by: Ruben Groenewoud <78494512+Aegrah@users.noreply.github.com>
* Update credential_access_lsass_openprocess_api.toml
* Update impact_hosts_file_modified.toml
* Update credential_access_dollar_account_relay.toml
* Update credential_access_new_terms_secretsmanager_getsecretvalue.toml
---------
Co-authored-by: Ruben Groenewoud <78494512+Aegrah@users.noreply.github.com>
This rule is evaluating the "new terms" against every individual role session, rather than against the Role itself. This is causing a massive volume of alerts
- updated rule description and investigation guide
- reduced execution window and interval
- replaced new terms from `user.id` to combination of `cloud.account.id` and `user.name` to account for evaluation against Roles and in the event that separate AWS accounts under the same Org reuse IAM user names. This will only evaluate the Role instead of each individual role session, which should greatly improve performance.
* [Rule Tuning] AWS Monthly Rule Tunings
* Adding several more AWS tunings
* updating patch version
* updating non-ecs type to boolean
* fixed cloudtrail index
Isai