From 8e2d4cbfc8d2848f0c7703315974e34e4d9c608b Mon Sep 17 00:00:00 2001 From: Craig Chamberlain Date: Tue, 22 Sep 2020 16:22:41 -0400 Subject: [PATCH] [New Rule] Unusual Linux System Owner or User Discovery Activity (#267) * Create ml_linux_system_user_discovery.toml ML rule to accompany the unusual system owner / user discovery job * Update rules/ml/ml_linux_system_user_discovery.toml Co-authored-by: Brent Murphy <56412096+bm11100@users.noreply.github.com> * Update ml_linux_system_user_discovery.toml added fp field * Update ml_linux_system_user_discovery.toml * Update ml_linux_system_user_discovery.toml * Update ml_linux_system_user_discovery.toml * Update ml_linux_system_user_discovery.toml lint * Update ml_linux_system_user_discovery.toml * Update rules/ml/ml_linux_system_user_discovery.toml Co-authored-by: Brent Murphy <56412096+bm11100@users.noreply.github.com> Co-authored-by: Brent Murphy <56412096+bm11100@users.noreply.github.com> --- rules/ml/ml_linux_system_user_discovery.toml | 43 ++++++++++++++++++++ 1 file changed, 43 insertions(+) create mode 100644 rules/ml/ml_linux_system_user_discovery.toml diff --git a/rules/ml/ml_linux_system_user_discovery.toml b/rules/ml/ml_linux_system_user_discovery.toml new file mode 100644 index 000000000..0a41b4a8f --- /dev/null +++ b/rules/ml/ml_linux_system_user_discovery.toml @@ -0,0 +1,43 @@ +[metadata] +creation_date = "2020/09/03" +ecs_version = ["1.6.0"] +maturity = "production" +updated_date = "2020/09/03" + +[rule] +anomaly_threshold = 75 +author = ["Elastic"] +description = """ +Looks for commands related to system user or owner discovery from an unusual user context. This can be due to uncommon +troubleshooting activity or due to a compromised account. A compromised account may be used to engage in system owner or +user discovery in order to identify currently active or primary users of a system. This may be a precursor to additional +discovery, credential dumping or privilege elevation activity. +""" +false_positives = [ + """ + Uncommon user command activity can be due to an engineer logging onto a server instance in order to perform manual + troubleshooting or reconfiguration. + """, +] +from = "now-45m" +interval = "15m" +license = "Elastic License" +machine_learning_job_id = "linux_system_user_discovery" +name = "Unusual Linux System Owner or User Discovery Activity" +risk_score = 21 +rule_id = "59756272-1998-4b8c-be14-e287035c4d10" +severity = "low" +tags = ["Elastic", "Linux", "ML"] +type = "machine_learning" +[[rule.threat]] +framework = "MITRE ATT&CK" +[[rule.threat.technique]] +id = "T1033" +name = "System Owner/User Discovery" +reference = "https://attack.mitre.org/techniques/T1033/" + + +[rule.threat.tactic] +id = "TA0007" +name = "Discovery" +reference = "https://attack.mitre.org/tactics/TA0007/"