Detect xrdp Unauthenticated Stack Buffer Overflow via RDP Connection Sequence (CVE-2025-68670) in Google Chronicle
CVE-2025-68670 is a critical unauthenticated stack buffer overflow (CWE-121) in xrdp versions prior to 0.10.5. During the RDP connection sequence, a remote unauthenticated attacker can send a specially crafted packet that overflows a stack buffer, potentially enabling remote code execution as the xrdp process user. CVSS 9.1. A public PoC exists. Patch to xrdp >= 0.10.5 immediately.
MITRE ATT&CK
- Tactic
- Initial Access Execution
YARA-L Detection Query
rule cve_2025_68670_xrdp_stack_overflow {
meta:
author = "df00tech"
description = "Detects potential exploitation of CVE-2025-68670 xrdp unauthenticated stack buffer overflow"
severity = "CRITICAL"
confidence = "MEDIUM"
reference = "https://github.com/neutrinolabs/xrdp/security/advisories/GHSA-rwvg-gp87-gh6f"
events:
(
$network.metadata.event_type = "NETWORK_CONNECTION"
$network.target.port = 3389
$network.network.direction = "INBOUND"
$network.principal.ip != "127.0.0.1"
)
or
(
$process.metadata.event_type = "PROCESS_UNCATEGORIZED"
re.regex($process.principal.process.file.full_path, `.*xrdp.*`)
re.regex($process.metadata.description, `(?i)(segfault|overflow|sigsegv|sigabrt|core dumped|fatal|crash)`)
)
condition:
$network or $process
}Chronicle YARA-L rule detecting inbound RDP connections to port 3389 and xrdp crash/signal events indicative of CVE-2025-68670 exploitation.
Data Sources
Required Tables
False Positives & Tuning
- Legitimate remote administration over RDP from known jump hosts
- xrdp service restarts during patching or maintenance
- RDP vulnerability scanners from authorized security tooling
- Non-exploit xrdp crashes from resource constraints
Other platforms for CVE-2025-68670
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.
- Test 1xrdp Version Enumeration via RDP Banner Grab
Expected signal: Network connection event to port 3389 from scanning host; xrdp access log entry for the probe connection.
- Test 2Malformed RDP X.224 PDU Fuzzing (PoC Simulation)
Expected signal: xrdp crash log entry (SIGSEGV/SIGABRT/stack smashing detected) in /var/log/xrdp.log; core dump if ulimit -c unlimited is set; network connection event from test host to port 3389.
- Test 3Post-Exploitation Persistence Check (Simulated RCE Artifact)
Expected signal: Auditd events for crontab modification by xrdp user; file creation event in /tmp for .xrdp_persist; process execution telemetry showing crontab -r invoked by non-interactive xrdp session.
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