Jonhnathan
7c90f1d4c4
* Initial commit
* Update Investigation guides - security-docs review
* Update command_and_control_dns_tunneling_nslookup.toml
* Update defense_evasion_amsienable_key_mod.toml
* Apply security-docs review
* Remove dot
* Update rules/windows/command_and_control_rdp_tunnel_plink.toml
Co-authored-by: nastasha-solomon <79124755+nastasha-solomon@users.noreply.github.com>
* Apply changes from review
* Apply the suggestion
Co-authored-by: nastasha-solomon <79124755+nastasha-solomon@users.noreply.github.com>
(cherry picked from commit 817b97f428)
110 lines
4.9 KiB
TOML
110 lines
4.9 KiB
TOML
[metadata]
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creation_date = "2021/10/01"
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maturity = "production"
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updated_date = "2022/05/09"
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[rule]
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author = ["Elastic"]
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description = """
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Identifies the deletion of backup files, saved using third-party software, by a process outside of the backup suite.
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Adversaries may delete Backup files to ensure that recovery from a ransomware attack is less likely.
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"""
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false_positives = [
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"Certain utilities that delete files for disk cleanup or Administrators manually removing backup files.",
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]
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from = "now-9m"
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index = ["winlogbeat-*", "logs-endpoint.events.*", "logs-windows.*"]
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language = "eql"
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license = "Elastic License v2"
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name = "Third-party Backup Files Deleted via Unexpected Process"
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note = """## Triage and analysis
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### Investigating Third-party Backup Files Deleted via Unexpected Process
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Backups are a significant obstacle for any ransomware operation. They allow the victim to resume business by performing
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data recovery, making them a valuable target.
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Attackers can delete backups from the host and gain access to backup servers to remove centralized backups for the
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environment, ensuring that victims have no alternatives to paying the ransom.
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This rule identifies file deletions performed by a process that does not belong to the backup suite and aims to delete
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Veritas or Veeam backups.
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#### Possible investigation steps
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- Investigate the process execution chain (parent process tree) for unknown processes. Examine their executable files
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for prevalence, whether they are located in expected locations, and if they are signed with valid digital signatures.
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- Identify the user account that performed the action and whether it should perform this kind of action.
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- Contact the account owner and confirm whether they are aware of this activity.
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- Investigate other alerts associated with the user/host during the past 48 hours.
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- Check if any files on the host machine have been encrypted.
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### False positive analysis
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- This rule can be triggered by the manual removal of backup files and by removal using other third-party tools that are
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not from the backup suite. Exceptions can be added for specific accounts and executables, preferably tied together.
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### Related rules
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- Deleting Backup Catalogs with Wbadmin - 581add16-df76-42bb-af8e-c979bfb39a59
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- Volume Shadow Copy Deleted or Resized via VssAdmin - b5ea4bfe-a1b2-421f-9d47-22a75a6f2921
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- Volume Shadow Copy Deletion via PowerShell - d99a037b-c8e2-47a5-97b9-170d076827c4
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- Volume Shadow Copy Deletion via WMIC - dc9c1f74-dac3-48e3-b47f-eb79db358f57
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### Response and remediation
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- Initiate the incident response process based on the outcome of the triage.
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- Investigate credential exposure on systems compromised or used by the attacker to ensure all compromised accounts are
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identified. Reset passwords for these accounts and other potentially compromised credentials, such as email, business
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systems, and web services.
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- Consider isolating the involved host to prevent destructive behavior, which is commonly associated with this activity.
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- Perform data recovery locally or restore the backups from replicated copies (Cloud, other servers, etc.).
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- Run a full antimalware scan. This may reveal additional artifacts left in the system, persistence mechanisms, and
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malware components.
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- Determine the initial vector abused by the attacker and take action to prevent reinfection through the same vector.
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- Using the incident response data, update logging and audit policies to improve the mean time to detect (MTTD) and the
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mean time to respond (MTTR).
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## Config
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If enabling an EQL rule on a non-elastic-agent index (such as beats) for versions <8.2, events will not define `event.ingested` and default fallback for EQL rules was not added until 8.2, so you will need to add a custom pipeline to populate `event.ingested` to @timestamp for this rule to work.
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"""
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references = ["https://www.advintel.io/post/backup-removal-solutions-from-conti-ransomware-with-love"]
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risk_score = 47
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rule_id = "11ea6bec-ebde-4d71-a8e9-784948f8e3e9"
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severity = "medium"
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tags = ["Elastic", "Host", "Windows", "Threat Detection", "Impact"]
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timestamp_override = "event.ingested"
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type = "eql"
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query = '''
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file where event.type == "deletion" and
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(
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/* Veeam Related Backup Files */
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(file.extension : ("VBK", "VIB", "VBM") and
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not process.executable : ("?:\\Windows\\Veeam\\Backup\\*",
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"?:\\Program Files\\Veeam\\Backup and Replication\\*",
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"?:\\Program Files (x86)\\Veeam\\Backup and Replication\\*")) or
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/* Veritas Backup Exec Related Backup File */
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(file.extension : "BKF" and
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not process.executable : ("?:\\Program Files\\Veritas\\Backup Exec\\*",
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"?:\\Program Files (x86)\\Veritas\\Backup Exec\\*"))
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)
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'''
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[[rule.threat]]
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framework = "MITRE ATT&CK"
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[[rule.threat.technique]]
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id = "T1490"
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name = "Inhibit System Recovery"
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reference = "https://attack.mitre.org/techniques/T1490/"
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[rule.threat.tactic]
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id = "TA0040"
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name = "Impact"
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reference = "https://attack.mitre.org/tactics/TA0040/"
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