PUA - Rclone Execution

Status: test
Severity: high
Log source: product windows, category process_creation
Author: Bhabesh Raj, Sittikorn S, Aaron Greetham (@beardofbinary) - NCC Group
Source: github.com/SigmaHQ/sigma

Detects execution of RClone utility for exfiltration as used by various ransomwares strains like REvil, Conti, FiveHands, etc

MITRE ATT&CK coverage

Tactic	Techniques
Exfiltration	`T1567.002` Exfiltration Over Web Service: Exfiltration to Cloud Storage

Event coverage

Provider	Event	Title
Sysmon	Event ID 1	Process creation

Rule body yaml

title: PUA - Rclone Execution
id: e37db05d-d1f9-49c8-b464-cee1a4b11638
related:
    - id: a0d63692-a531-4912-ad39-4393325b2a9c
      type: obsolete
    - id: cb7286ba-f207-44ab-b9e6-760d82b84253
      type: obsolete
status: test
description: Detects execution of RClone utility for exfiltration as used by various ransomwares strains like REvil, Conti, FiveHands, etc
references:
    - https://research.nccgroup.com/2021/05/27/detecting-rclone-an-effective-tool-for-exfiltration/
    - https://thedfirreport.com/2021/03/29/sodinokibi-aka-revil-ransomware
    - https://us-cert.cisa.gov/ncas/analysis-reports/ar21-126a
    - https://labs.sentinelone.com/egregor-raas-continues-the-chaos-with-cobalt-strike-and-rclone
    - https://www.splunk.com/en_us/blog/security/darkside-ransomware-splunk-threat-update-and-detections.html
author: Bhabesh Raj, Sittikorn S, Aaron Greetham (@beardofbinary) - NCC Group
date: 2021-05-10
modified: 2023-03-05
tags:
    - attack.exfiltration
    - attack.t1567.002
logsource:
    product: windows
    category: process_creation
detection:
    selection_specific_options:
        CommandLine|contains|all:
            - '--config '
            - '--no-check-certificate '
            - ' copy '
    selection_rclone_img:
        - Image|endswith: '\rclone.exe'
        - Description: 'Rsync for cloud storage'
    selection_rclone_cli:
        CommandLine|contains:
            - 'pass'
            - 'user'
            - 'copy'
            - 'sync'
            - 'config'
            - 'lsd'
            - 'remote'
            - 'ls'
            - 'mega'
            - 'pcloud'
            - 'ftp'
            - 'ignore-existing'
            - 'auto-confirm'
            - 'transfers'
            - 'multi-thread-streams'
            - 'no-check-certificate '
    condition: selection_specific_options or all of selection_rclone_*
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: `condition`

selection_specific_options or all of selection_rclone_*

Stage 1: `selection_specific_options`

selection_specific_options:
    CommandLine|contains|all:
        - '--config '
        - '--no-check-certificate '
        - ' copy '

Stage 2: `selection_rclone_img`

selection_rclone_img:
    - Image|endswith: '\rclone.exe'
    - Description: 'Rsync for cloud storage'

Stage 3: `selection_rclone_cli`

selection_rclone_cli:
    CommandLine|contains:
        - 'pass'
        - 'user'
        - 'copy'
        - 'sync'
        - 'config'
        - 'lsd'
        - 'remote'
        - 'ls'
        - 'mega'
        - 'pcloud'
        - 'ftp'
        - 'ignore-existing'
        - 'auto-confirm'
        - 'transfers'
        - 'multi-thread-streams'
        - 'no-check-certificate '

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
`CommandLine`	match	`copy` corpus 4 (sigma 4) `--config` `--no-check-certificate` `auto-confirm` `config` corpus 16 (sigma 15, splunk 1) `copy` corpus 5 (sigma 4, chronicle 1) `ftp` corpus 2 (sigma 2) `ignore-existing` `ls` `lsd` `mega` `multi-thread-streams` `no-check-certificate` `pass` corpus 2 (sigma 2) `pcloud` `remote` `sync` `transfers` `user` corpus 17 (sigma 11, splunk 4, chronicle 2)
`Description`	eq	`Rsync for cloud storage`
`Image`	ends_with	`\rclone.exe`

`j` / `k`	Scroll down / up
`d` / `u`	Half-page down / up
`gg` / `G`	Top / bottom
`h` / `l`	History back / forward
`f`	Follow link (`Shift` = new tab)
`/`	Focus search
`?`	Toggle this help
`↑` / `↓`	Navigate search results
`Enter`	Open highlighted result
`Esc`	Close results / dialog

`type:`	`events` / `rules` / `providers`
`vendor:`	`sigma` / `elastic` / `splunk` / `kusto` / `chronicle` (vendor name alone also works: `sigma:`, `kql:`, `secops:`…)
`tactic:`	TA-id, slug, or name: `credential_access`, `TA0006`
`technique:`	technique or sub-technique ID: `T1003`, `T1003.001` (alias `tech:`)
`severity:`	`critical` / `high` / `medium` / `low` / `informational` (alias `sev:`)
`risk_score`	Numeric comparison on the Elastic risk score (0 to 100): `risk_score>50`, `risk_score<=20`, `risk_score=99` (alias `risk`; Elastic rules only)
`stages:`	Rules with exactly N pipeline stages
`correlation:`	`single_event` / `sequence` / `alternatives` / `alternatives_cross_log` / `all_required` / `correlated`
`with:`	Co-occurrence event-id; stacks (`with:4624 with:4769`) to require all, while a comma list in one occurrence (`with:4624,4769`) is an either-or group. Implies multi-event
`like:`	Structural neighbors of a rule slug (equivalents + subsumption stricter / broader): `like:comsvcs_lsass_memory_dump-splunk-sysmon`
`groupby:`	Entity-grouping substring match against `group_by_keys`: `groupby:user`, `groupby:host`
`uses:`	Rules whose predicate tree touches the field (any kind, any value): `uses:CommandLine`
`excludes:`	Rules with top-level `not()` clauses on the field (FP whitelists): `excludes:ParentImage`
`field:` / `value:`	Predicate search; narrows rule cards to those with a matching leaf and drives the indicator tier. Unquoted = substring, wildcards allowed (`value:mimikatz`)
`indicator:`	Shorthand for `field:F value:V`: `indicator:Image=*\powershell.exe`
`kind:`	Filter by predicate kind. Narrows rule cards to those carrying a matching predicate leaf (`vendor:elastic kind:cidr_match`) and drives the indicator tier: `contains` / `starts_with` / `ends_with` / `regex` / `cidr` / `eq` / `in` … (operator aliases `op:`/`match:`)
`has:` / `no:`	`sample`, `field`, `notes`, `refs`, `trace`, `thirdparty`, `rule`, `pattern`, `timewindow`, `threshold`, `newterms`, `sigma`/`elastic`/`splunk`/`kusto`/`chronicle`
`-op:val`	Exclude matches; works on most operators but not `type:`/`like:`/`has:`/`no:` (use `no:<flag>` to exclude a rule flag): `tactic:execution -vendor:splunk`. Standalone `-kind:`/`-field:`/`-value:` drop every rule carrying a matching predicate leaf (`type:rules -kind:is_null`)
`field:"…"` / `value:"…"`	Quoted value = anchored exact match (also allows spaces): `value:"net user"`
`a,b`	Comma = OR inside one operator (`vendor:sigma,elastic`, `severity:high,critical`); repeating a facet merges the same way. `field:`/`value:` never split (literal commas)
`vendors:` / `stage:`	Singular and plural spellings fold to the canonical operator and value: `tactics:` = `tactic:`, `type:event` = `type:events`, `correlation:sequences` = `correlation:sequence`, `has:thresholds` = `has:threshold`
`"quoted phrase"`	Exact-match a multi-word phrase (free text)

PUA - Rclone Execution

MITRE ATT&CK coverage

Event coverage

Rule body yaml

Stages and Predicates

Stage 0: `condition`

Stage 1: `selection_specific_options`

Stage 2: `selection_rclone_img`

Stage 3: `selection_rclone_cli`

Indicators

Keyboard shortcuts

Search operators

PUA - Rclone Execution

MITRE ATT&CK coverage

Event coverage

Rule body yaml

Stages and Predicates

Stage 0: condition

Stage 1: selection_specific_options

Stage 2: selection_rclone_img

Stage 3: selection_rclone_cli

Indicators

Stage 0: `condition`

Stage 1: `selection_specific_options`

Stage 2: `selection_rclone_img`

Stage 3: `selection_rclone_cli`