USN-6866-3: Linux kernel (Azure) vulnerabilities

It was discovered that the ext4 file system implementation in the Linux
kernel did not properly validate data state on write operations. An
attacker could use this to construct a malicious ext4 file system image
that, when mounted, could cause a denial of service (system crash).
(CVE-2021-33631)

It was discovered that the ATA over Ethernet (AoE) driver in the Linux
kernel contained a race condition, leading to a use-after-free
vulnerability. An attacker could use this to cause a denial of service or
possibly execute arbitrary code. (CVE-2023-6270)

Sander Wiebing, Alvise de Faveri Tron, Herbert Bos, and Cristiano Giuffrida
discovered that the Linux kernel mitigations for the initial Branch History
Injection vulnerability (CVE-2022-0001) were insufficient for Intel
processors. A local attacker could potentially use this to expose sensitive
information. (CVE-2024-2201)

Gui-Dong Han discovered that the software RAID driver in the Linux kernel
contained a race condition, leading to an integer overflow vulnerability. A
privileged attacker could possibly use this to cause a denial of service
(system crash). (CVE-2024-23307)

Bai Jiaju discovered that the Xceive XC4000 silicon tuner device driver in
the Linux kernel contained a race condition, leading to an integer overflow
vulnerability. An attacker could possibly use this to cause a denial of
service (system crash). (CVE-2024-24861)

Several security issues were discovered in the Linux kernel.
An attacker could possibly use these to compromise the system.
This update corrects flaws in the following subsystems:
- Block layer subsystem;
- Hardware random number generator core;
- GPU drivers;
- AFS file system;
- Memory management;
- Netfilter;
(CVE-2024-26642, CVE-2024-26922, CVE-2024-26720, CVE-2024-26736,
CVE-2024-26898, CVE-2021-47063, CVE-2023-52615)

nmap -sV --script vuln -p- <target-network>

tail -f /var/log/suricata/fast.log | grep <cve>

Check Vendor Security Advisory Bulletin

title: Detect Exploitation - USN-6866-3: Linux kernel (Azure) vulnerabilities
id: 5b31f813-3fbd-4635-bf16-8dc6a787ea8b
status: experimental
description: Automatisch generierte SIEM-Erkennungsregel basierend auf CTI Intelligence
references:
  - https://tsecurity.de/
author: iShareStuff CTI Automated Detection Engine
date: 2026-09-24
logsource:
  category: network_connection
  product: any
detection:
  selection:
      CommandLine|contains:
        - 'exploit'
  condition: selection
falsepositives:
  - Legitime administrative Zugriffe oder Penetrationstests
level: high
tags:
  - attack.initial_access

rule CTI_Threat_Indicator {
    meta:
        author = "iShareStuff CTI Automated Detection Engine"
        date = "2026-09-24"
        description = "YARA Signature for "
    strings:
        $str = "USN-6866-3: Linux kernel (Azur" ascii wide
    condition:
        any of them
}

index=security sourcetype IN ("cisco:asa", "pan:traffic", "zeek_conn", "suricata", "WinEventLog:Security")
("USN-6866-3 Linux kernel Azure vulnerabil")
| stats count earliest(_time) as first_seen latest(_time) as last_seen by src_ip, dest_ip, dest_host, signature
| eval first_seen=strftime(first_seen, "%Y-%m-%d %H:%M:%S"), last_seen=strftime(last_seen, "%Y-%m-%d %H:%M:%S")
| sort - count

message: "*USN-6866-3 Linux kernel Azure vulnerabil*"

CommonSecurityLog
| where Message has "USN-6866-3 Linux kernel Azure vulnerabil"
| summarize EventCount = count(), FirstSeen = min(TimeGenerated), LastSeen = max(TimeGenerated) by SourceIP, DestinationIP, DestinationPort, Activity
| extend DetectionRule = "iShareStuff-CTI-Compiled"
| sort by EventCount desc

#!/usr/sbin/nft -f
# ISS-ZeroTrust Quarantine Policy for CVE-2021-33631
table inet iss_quarantine {
    chain inbound_lockdown {
        type filter hook input priority -10; policy drop;

        # Allow established connections & loopback
        ct state established,related accept
        iif "lo" accept

        # Whitelist SOC / Bastion Management Subnet
        ip saddr 10.0.0.0/8 accept
        ip saddr 192.168.1.0/24 accept

        # Explicitly log & drop vulnerable service traffic
        tcp dport 443 log prefix "[ISS-QUARANTINE-CVE-2021-33631] " drop
    }
}

apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: quarantine-CVE-2021-33631
  namespace: production
  labels:
    security.isharestuff.com/quarantine: "true"
    cve.mitigation/id: "CVE-2021-33631"
spec:
  podSelector:
    matchLabels:
      app.kubernetes.io/vulnerable-cve: "CVE-2021-33631"
  policyTypes:
    - Ingress
    - Egress
  ingress:
    # Restrict ingress solely to authorized security scanners & bastion pods
    - from:
        - namespaceSelector:
            matchLabels:
              kubernetes.io/metadata.name: soc-monitoring
      ports:
      - port: 443
        protocol: TCP
  egress:
    # Allow DNS only (isolate lateral movement)
    - to:
        - namespaceSelector: {}
          podSelector:
            matchLabels:
              k8s-app: kube-dns
      ports:
        - port: 53
          protocol: UDP

aws ec2 revoke-security-group-ingress --group-id sg-0123456789abcdef0 --protocol tcp --port 443 --cidr 0.0.0.0/0

(http.request.uri.path contains "CVE-2021-33631" or http.request.body.mime contains "exploit" or cf.threat_score gt 20)