Samirbous
50bb821708
* [Rules Tuning] Add support for Sysmon ImageLoad Events added correct event.category and event.action to rules using library events to support sysmon eventid 7. `event.category == "library"` --> `(event.category == "process" and event.action : "Image loaded*")` `dll.name` --> `file.name` * added Suspicious RDP ActiveX Client Loaded * Delete workspace.xml
104 lines
5.2 KiB
TOML
Executable File
104 lines
5.2 KiB
TOML
Executable File
[metadata]
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creation_date = "2020/03/25"
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maturity = "production"
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updated_date = "2022/08/02"
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[rule]
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author = ["Elastic"]
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description = """
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An instance of MSBuild, the Microsoft Build Engine, loaded DLLs (dynamically linked libraries) responsible for Windows
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credential management. This technique is sometimes used for credential dumping.
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"""
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false_positives = ["The Build Engine is commonly used by Windows developers but use by non-engineers is unusual."]
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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 = "Potential Credential Access via Trusted Developer Utility"
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note = """## Triage and analysis
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### Investigating Potential Credential Access via Trusted Developer Utility
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The Microsoft Build Engine is a platform for building applications. This engine, also known as MSBuild, provides an XML
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schema for a project file that controls how the build platform processes and builds software.
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Adversaries can abuse MSBuild to proxy the execution of malicious code. The inline task capability of MSBuild that was
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introduced in .NET version 4 allows for C# or Visual Basic code to be inserted into an XML project file. MSBuild will
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compile and execute the inline task. `MSBuild.exe` is a signed Microsoft binary, and the execution of code using it can bypass
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application control defenses that are configured to allow `MSBuild.exe` execution.
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This rule looks for the MSBuild process loading `vaultcli.dll` or `SAMLib.DLL`, which indicates the execution of
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credential access activities.
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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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- Investigate abnormal behaviors observed by the subject process, such as network connections, registry or file
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modifications, and any spawned child processes.
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- Investigate other alerts associated with the user/host during the past 48 hours.
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- Examine the command line to identify the `.csproj` file location.
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- Retrieve the file and determine if it is malicious:
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- Use a private sandboxed malware analysis system to perform analysis.
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- Observe and collect information about the following activities:
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- Attempts to contact external domains and addresses.
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- File and registry access, modification, and creation activities.
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- Service creation and launch activities.
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- Scheduled tasks creation.
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- Use the PowerShell Get-FileHash cmdlet to get the files' SHA-256 hash values.
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- Search for the existence and reputation of the hashes in resources like VirusTotal, Hybrid-Analysis, CISCO Talos, Any.run, etc.
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- Investigate potentially compromised accounts. Analysts can do this by searching for login events (for example, 4624) to the target
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host after the registry modification.
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### False positive analysis
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- This activity is unlikely to happen legitimately. Benign true positives (B-TPs) can be added as exceptions if necessary.
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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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- Isolate the involved hosts to prevent further post-compromise behavior.
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- If the triage identified malware, search the environment for additional compromised hosts.
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- Implement temporary network rules, procedures, and segmentation to contain the malware.
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- Stop suspicious processes.
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- Immediately block the identified indicators of compromise (IoCs).
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- Inspect the affected systems for additional malware backdoors like reverse shells, reverse proxies, or droppers that
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attackers could use to reinfect the system.
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- Remove and block malicious artifacts identified during 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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- 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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"""
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risk_score = 73
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rule_id = "9d110cb3-5f4b-4c9a-b9f5-53f0a1707ae5"
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severity = "high"
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tags = ["Elastic", "Host", "Windows", "Threat Detection", "Credential Access"]
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type = "eql"
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query = '''
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sequence by process.entity_id
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[process where event.type == "start" and (process.name : "MSBuild.exe" or process.pe.original_file_name == "MSBuild.exe")]
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[any where (event.category == "library" or (event.category == "process" and event.action : "Image loaded*")) and
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(dll.name : ("vaultcli.dll", "SAMLib.DLL") or file.name : ("vaultcli.dll", "SAMLib.DLL"))]
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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 = "T1003"
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reference = "https://attack.mitre.org/techniques/T1003/"
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name = "OS Credential Dumping"
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[rule.threat.tactic]
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id = "TA0006"
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reference = "https://attack.mitre.org/tactics/TA0006/"
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name = "Credential Access"
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