SecBoard
Zurück zur CVE-Übersicht

CVE-2026-98420

NONE
Risk Signal Score0/100 — NIEDRIG

Erwähnungen (letzte 60 Tage)

Artikel

EPSS-Score

0.2%

Exploit-Wahrscheinlichkeit (30 Tage)

Beschreibung

In the Linux kernel, the following vulnerability has been resolved: ksmbd: follow SMB2 session expiration semantics ksmbd_session_register() destroys valid sessions after ten seconds of inactivity whenever a client starts another SessionSetup exchange. This confuses Session.IdleTime with Session.ExpirationTime. Windows can create additional authenticated sessions on an existing connection, so deleting the older session invalidates its tree connects and makes mapped drives fail with STATUS_NETWORK_NAME_DELETED. The session expiration rules require the server to change a valid session to expired only after its credential expiration time passes. A valid or expired session otherwise keeps its connection from being scavenged. Connections that have not negotiated a dialect, have no sessions, or have only InProgress sessions are disconnected after an implementation-specific timeout. Use the Windows-compatible 45 second value and run the expiration check periodically for both TCP and SMB Direct. Keep zero as an infinite credential expiration time, and count each Valid-to-Expired transition. Set expired sessions to InProgress when they reauthenticate. If authentication fails, remove the session from the global and per-connection tables immediately, including SMB3 multichannel connections. Retain protection against abandoned SessionId-zero exchanges by allowing only one InProgress authentication per connection. Additional exchanges fail with STATUS_INSUFFICIENT_RESOURCES, and stale InProgress sessions are reaped after the same 45 second setup timeout. This bounds the original unauthenticated memory-exhaustion path without evicting established sessions.

Erkennung & Indikatoren

Ausnutzung

In den geprüften Quellen nicht genannt

Threat-Hunting-Queries

This query detects failed SMB tree connects due to session invalidation, which could be a symptom of the described ksmbd vulnerability. It requires logging of SMB server events that indicate connection failures or session issues.

Sentinel/Defender KQL

DeviceNetworkEvents
| where Protocol == "SMB" and ActionType == "ConnectionFailed"
| where AdditionalFields contains "STATUS_NETWORK_NAME_DELETED"
| summarize count() by DeviceName, RemoteIP, InitiatingProcessFileName

Splunk SPL

index=* sourcetype=smb (status_code="STATUS_NETWORK_NAME_DELETED" OR message="mapped drives fail")
| stats count by host, src_ip

Sigma

title: Ksmbd Session Expiration Issue
id: 00000000-0000-0000-0000-000000000000
status: experimental
description: Detects potential ksmbd session expiration issues leading to STATUS_NETWORK_NAME_DELETED errors.
author: SecBoard
date: 2026/09/25
logsource:
  category: network_connection
  product: linux
detection:
  selection:
    Protocol: "SMB"
    EventData|contains: "STATUS_NETWORK_NAME_DELETED"
  condition: selection
fields:
  - ComputerName
  - SourceIp
  - DestinationIp
tags:
  - attack.defense_evasion
  - cve.2026.98420

Elastic ES|QL

from network where event.dataset == "smb" and event.action == "connection_failed" and error.message : "STATUS_NETWORK_NAME_DELETED" | stats count() by host.name, source.ip, destination.ip

SecBoard-generated · behavioral · requires customization — Von SecBoard erzeugt und nicht in einer Zielumgebung validiert. Vor dem Einsatz an die eigene Protokollierung anpassen.

Indikatoren

Domains (1)

  • mobintestserver.ir

Übernommen wurden nur Indikatoren, die wörtlich in einer Hersteller- oder Research-Quelle standen.

Referenzen