CVE-2026-49980 Microsoft Sentinel · KQL

Detect Rclone RCD Unauthenticated Command Execution via Inline Remote Instantiation (CVE-2026-49980) in Microsoft Sentinel

CVE-2026-49980 is a critical unauthenticated remote code execution vulnerability in Rclone versions 1.46.0 through 1.74.2. When the rclone remote control daemon (rcd) is started with the --rc-serve flag, an attacker can instantiate arbitrary remotes inline via the RC API without authentication, bypassing the fix introduced for CVE-2026-41179. This allows execution of arbitrary commands on the host running rclone rcd. CVSS 9.8. PoC is publicly available.

MITRE ATT&CK

Tactic
Initial Access Execution Lateral Movement

KQL Detection Query

Microsoft Sentinel (KQL)
kusto 
union DeviceNetworkEvents, DeviceProcessEvents
| where TimeGenerated > ago(7d)
| where (
    (ActionType == "NetworkConnectionInitiated" and RemotePort == 5572)
    or (FileName in~ ("rclone", "rclone.exe") and ProcessCommandLine has_any ("rcd", "rc-serve", "--rc-serve"))
  )
| extend IsRCDProcess = (FileName in~ ("rclone", "rclone.exe") and ProcessCommandLine has_any ("rcd", "--rc-serve"))
| extend IsNetworkHit = (ActionType == "NetworkConnectionInitiated" and RemotePort == 5572)
| project TimeGenerated, DeviceName, InitiatingProcessAccountName, FileName, ProcessCommandLine, RemoteIP, RemotePort, LocalIP, LocalPort, ActionType, IsRCDProcess, IsNetworkHit
| where IsRCDProcess == true or IsNetworkHit == true
critical severity high confidence

Detects rclone processes started with rcd/--rc-serve flags and inbound network connections to the default RC API port (5572), indicative of CVE-2026-49980 exploitation attempts.

Data Sources

Microsoft Defender for EndpointMicrosoft Sentinel DeviceProcessEventsMicrosoft Sentinel DeviceNetworkEvents

Required Tables

DeviceProcessEventsDeviceNetworkEvents

False Positives & Tuning

  • Legitimate administrators using rclone rcd with authentication properly configured
  • Automated backup or sync pipelines that use rclone rcd internally with firewall controls
  • CI/CD pipelines running rclone for cloud storage operations with --rc-serve enabled in controlled environments

Other platforms for CVE-2026-49980

Splunk (SPL) Elastic Security (Elastic) IBM QRadar (QRadar) Sumo Logic CSE (Sumo) Google Chronicle (YARA-L) CrowdStrike LogScale (LogScale) All platforms (combined) →

Testing Methodology

Validate this detection against 3 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.

  1. Test 1Unauthenticated rclone rcd RC API probe

    Expected signal: Process creation event for rclone with arguments including rcd and --rc-no-auth; network bind event on port 5572; outbound HTTP POST to 127.0.0.1:5572

  2. Test 2Inline remote instantiation via unauthenticated RC API

    Expected signal: HTTP POST to /config/create on port 5572; rclone process spawned with --rc-no-auth; possible rclone.conf modification event

  3. Test 3Remote command execution via rclone RC /core/command endpoint

    Expected signal: HTTP POST to /core/command; rclone process with --rc-no-auth flag in process tree; network event on port 5572 from unexpected source

Last updated: 2026-06-21 Research depth: standard
References (2)

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Tactic Hubs

TA0001Initial AccessTA0002ExecutionTA0008Lateral Movement

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Same Tactic: Initial Access

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