Detection rules › Splunk
Sliver C2 Implant Activity Pattern (Sysmon)
Adversaries may abuse command and script interpreters to execute commands, scripts, or binaries. These interfaces and languages provide ways of interacting with computer systems and are a common feature across many different platforms. Most systems come with some built-in command-line interface and scripting capabilities, for example, macOS and Linux distributions include some flavor of Unix Shell while Windows installations include the Windows Command Shell and PowerShell. This use case detects process activity patterns related to Sliver C2 framework implants when spawning PowerShell.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Execution | T1059 Command and Scripting Interpreter |
References
- https://attack.mitre.org/techniques/T1059/
- https://github.com/BishopFox/sliver/blob/master/implant/sliver/shell/shell_windows.go#L39
- https://sliver.sh/docs?name=Compile+from+Source
- https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_hktl_sliver_c2_execution_pattern.yml
Event coverage
| Provider | Event | Title |
|---|---|---|
| Sysmon | Event ID 1 | Process creation |
Rule body yaml
id: '38206.68755'
title: Sliver C2 Implant Activity Pattern
description: Adversaries may abuse command and script interpreters to execute commands,
scripts, or binaries. These interfaces and languages provide ways of interacting
with computer systems and are a common feature across many different platforms.
Most systems come with some built-in command-line interface and scripting capabilities,
for example, macOS and Linux distributions include some flavor of Unix Shell while
Windows installations include the Windows Command Shell and PowerShell. This use
case detects process activity patterns related to Sliver C2 framework implants when
spawning PowerShell.
logic_format: Splunk
logic: '`get_endpoint_data` `get_endpoint_data_sysmon` (TERM(EventCode=1) OR "<EventID>1<")
"-NoExit" "-Command" "[Console]::OutputEncoding=[Text.UTF8Encoding]::UTF8" | table
_time, host, user, parent_*, process, process_* | bin span=1s | stats values(*)
as * by _time, host '
techniques:
- execution:command and scripting interpreter
technique_id:
- T1059
data_category:
- Windows Sysmon
references:
- https://attack.mitre.org/techniques/T1059/
- https://github.com/BishopFox/sliver/blob/master/implant/sliver/shell/shell_windows.go#L39
- https://sliver.sh/docs?name=Compile+from+Source
- https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_hktl_sliver_c2_execution_pattern.yml
Stages and Predicates
Stage 1: search
`get_endpoint_data` `get_endpoint_data_sysmon` (TERM(EventCode=1) OR "<EventID>1<") "-NoExit" "-Command" "[Console]::OutputEncoding=[Text.UTF8Encoding]::UTF8"
Stage 2: table
| table _time, host, user, parent_*, process, process_*
Stage 3: bucket
| bin span=1s
Stage 4: stats
| stats values(*) as * by _time, host
Indicators
Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.
| Field | Kind | Values |
|---|---|---|
EventCode | eq |
|
Search terms
Bare-string tokens in the SPL search body. Splunk matches each token against _raw (the untyped raw event text) anywhere it appears, not against a specific field. These don't surface in the Indicators table because they aren't predicates on a known field.
| Stage | Term |
|---|---|
| 1 | TERM |
| 1 | "<EventID>1<" |
| 1 | "-NoExit" |
| 1 | "-Command" |
| 1 | "[Console]::OutputEncoding=[Text.UTF8Encoding]::UTF8" |