Telnet Authentication Bypass via User Environment Variable
Identifies potential exploitation of a Telnet remote authentication bypass vulnerability (CVE-2026-24061) in GNU Inetutils telnetd. The vulnerability allows unauthenticated access by supplying a crafted `-f…
Description
Identifies potential exploitation of a Telnet remote authentication bypass vulnerability (CVE-2026-24061) in GNU Inetutils telnetd. The vulnerability allows unauthenticated access by supplying a crafted `-f <username>` value via the `USER` environment variable, resulting in a login process spawned with elevated privileges.
Detection logic
Its licence does not clear it for publishing here
Sunturai publishes a detection's own text where the licence it arrived under has been reviewed and permits it, and Elastic License 2.0 has not. The query as its source wrote it, its canonical form and the hash that pins this revision are in the workspace record.
Detection requirements
- Platform
- ContainersESXiIaaSLinuxmacOSNetwork DevicesWindows
The rule states no platform. This is derived from the 3 ATT&CK techniques it maps to.
- Log source category
- event_index
MITRE ATT&CK mappings
0 exclusive techniques.This is coverage no other published rule has; it is not this rule's total technique count.
References
| Reference | Cited by |
|---|---|
| security-tracker.debian.org/tracker/CVE-2026-24061 | 2 |
| www.safebreach.com/blog/safebreach-labs-root-cause-analysis-and-poc-exploit-for-cve-2026-24061/ | 3from 2 sources |
From the source
- At source
- Open at source
- Upstream identifier
- eb3150eb-e9fb-4a64-a0fc-aa66cdd35632
- Tagged by the source as
- Data Source: Auditd ManagerDomain: EndpointNoise: LowOS: LinuxPerformance: NormalPlatform: LinuxProfile: RecommendedResources: Investigation GuideRule Type: Event Correlation (EQL)Tactic: Initial AccessTactic: Lateral MovementThreat: Vulnerability ExploitUse Case: Threat DetectionUse Case: VulnerabilityVuln: CVE-2026-24061
Licence
- Published under
- Elastic License 2.0Read the licence
- Attribution
- Required
Authorship
- Written by
- Published
- Sep 20, 2026
- Version
- 3