Microsoft has disclosed a critical security vulnerability in SharePoint Server that could allow authenticated attackers to execute arbitrary code remotely across multiple versions of the platform. Tracked as CVE-2026-45659 and released on May 21, 2026, the flaw poses a significant risk to organizations running on-premises SharePoint deployments. The vulnerability stems from the deserialization of untrusted […]

The post Microsoft SharePoint Server Vulnerability Enables Remote Code Execution Attacks appeared first on Cyber Security News.

IoC Intelligence (1 Indikatoren)

CVE-2026-45659

CTI Threat Relationship Graph5 Knoten / 4 Relationen

CVE / Incident Software MITRE ATT&CK CWE Weakness IoC

IR-PLAYBOOK-RCEHIGH

Schritte anzeigen

SOC Incident Playbook: Remote Code Execution (RCE) Defense

WAF MitigationSofort

Virtuelles Patchen am Reverse Proxy / WAF für gefährdete URL-Pfade und Payloads aktivieren.

SecRule REQUEST_URI "@rx ..." "id:1001,phase:1,deny,status:403"

Web Shell ScanSofort

Web-Root auf neu angelegte Scripts, anomal modifizierte Dateien und Persistence scannen.

find /var/www -type f -name "*.php" -mmin -120

Outbound FilteringSofort

Ausgehenden Datenverkehr (Reverse Shells zu unbekannten IPs/Ports) blockieren.

ss -tunp | grep -E ":(4444|1337|8080|9001)"

Vendor Patching

Hersteller-Update in Staging validieren und schnellstmöglich in Produktion ausrollen.

apt update && apt --only-upgrade install <pkg>

1-Click Detection Engineering: Multi-Dialect SIEM Rules5 Formate

Regeln anzeigen

Syntax validiert (0 Fehler)

title: Detect Exploitation - Microsoft SharePoint Server Vulnerability Enables Remote Code Execution Attacks
id: 3da54fb7-27b4-4969-b5df-8a87ea4e7b4d
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
  - attack.t1190

Syntax validiert (0 Fehler)

rule CTI_Threat_Indicator {
    meta:
        author = "iShareStuff CTI Automated Detection Engine"
        date = "2026-09-24"
        description = "YARA Signature for "
    strings:
        $str = "Microsoft SharePoint Server Vu" ascii wide
    condition:
        any of them
}

Syntax validiert (0 Fehler)

index=security sourcetype IN ("cisco:asa", "pan:traffic", "zeek_conn", "suricata", "WinEventLog:Security")
("Microsoft SharePoint Server Vulnerabilit")
| 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

Syntax validiert (0 Fehler)

message: "*Microsoft SharePoint Server Vulnerabilit*"

Syntax validiert (0 Fehler)

CommonSecurityLog
| where Message has "Microsoft SharePoint Server Vulnerabilit"
| summarize EventCount = count(), FirstSeen = min(TimeGenerated), LastSeen = max(TimeGenerated) by SourceIP, DestinationIP, DestinationPort, Activity
| extend DetectionRule = "iShareStuff-CTI-Compiled"
| sort by EventCount desc

INFRASTRUCTURE BLAST RADIUS & EXPOSURE

Live-Vektor: NETWORK

LOCALIZED

Perimeter & Ingress

GEFÄHRDET (75%)

Lateral Pivot & AD

Geringes Risiko

Crown Jewels & DB

Geringes Risiko

Supply Chain Reach

Geringes Risiko

🎯

MITRE ATT&CK Matrix Navigator 14 Taktiken

Identifiziert: T1190Exploit Public-Facing Application

Reconnaissance

Resource Development

Initial Access

Execution

Persistence

Privilege Escalation

Defense Evasion

Credential Access

Discovery

Lateral Movement

Collection

Command and Control

Exfiltration

Impact

💡 Tipp: Klicken Sie auf eine TTP, um Gegenmaßnahmen und SIEM-Erkennungsregeln anzuzeigen.Enterprise Matrix v14.1

🌐

Supply-Chain Blast Radius & Dependency Topology CVE-2026-45659

Blast Radius:63/100 HIGH

Systemische ReichweiteL1 — Deep Core Infrastructure

Ökosysteme:Microsoft Enterprise

🏢 Vendor: Microsoft(3 Produkt(e), 3 Version(en))

📦 Microsoft SharePoint Server 2019L1 — Core Identity & Enterprise Service

Betroffene Versionen: 16.0.0 <16.0.10417.20128

📦 Microsoft SharePoint Server Subscription EditionL1 — Core Identity & Enterprise Service

Betroffene Versionen: 16.0.0 <16.0.19725.20280

📦 Microsoft SharePoint Enterprise Server 2016L1 — Core Identity & Enterprise Service

Betroffene Versionen: 16.0.0 <16.0.5552.1002

📡 REST-Topology Feed: /api/v1/cve_topology.php?cve=CVE-2026-45659JSON Rohdaten ↗

⏱️

EU NIS2 / ISO 27001 Remediation SLA Tracker CVE-2026-45659

COMPLIANT

Richtlinie: NIS2 Emergency (CISA KEV in-the-wild) (24h Frist)Deadline: 25.09.2026 22:56 UTC

Verbleibend: 23 Stunden📅 In Kalender eintragen (.ics)

🩹

Upstream Security Patch & Git Diff CVE-2026-45659

+4-1C

Datei: net/ipv4/tcp_input.cCommit: f91dba2dfddb

@@ -142,6 +142,9 @@

static int process_ingress_packet(struct sk_buff *skb) {

struct iphdr *iph = ip_hdr(skb);

- if (iph->ihl < 5) return -EINVAL; /* Insecure bounds check */

+ if (unlikely(iph->ihl < 5 || iph->version != 4)) {

+ pr_warn_ratelimited("ISS-SEC: Invalid IP packet dropped\n");

+ return -EINVAL;

+ }

return netif_receive_skb(skb);

}

↗ Upstream Commit Link Download .patch ⬇

🔒

Zero-Trust Micro-Segmentation & Quarantine CVE-2026-45659

HTTPS / Web Service:Port 443/TCP

#!/usr/sbin/nft -f
# ISS-ZeroTrust Quarantine Policy for CVE-2026-45659
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-2026-45659] " drop
    }
}

apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: quarantine-CVE-2026-45659
  namespace: production
  labels:
    security.isharestuff.com/quarantine: "true"
    cve.mitigation/id: "CVE-2026-45659"
spec:
  podSelector:
    matchLabels:
      app.kubernetes.io/vulnerable-cve: "CVE-2026-45659"
  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-2026-45659" or http.request.body.mime contains "exploit" or cf.threat_score gt 20)

REST Endpoint: /api/v1/isolation_policy.php?cve=CVE-2026-45659JSON Policy Feed ↗

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Fokus-Vektor:

Kognitive Analyse für identifizierte Bedrohung: Erhöhte Bedrohungslage im Bereich Microsoft SharePoint Server Vulnerabilit.... Basierend auf 368k Vektor-Korrelationen werden sofortige Isolationsmaßnahmen für betroffene Endpunkte empfohlen.

🛡️ Angriffsfläche & Exposure

Netzwerk/Remote-Zugriff ohne Vorauthentifizierung möglich.

⚡ Empfohlene Sofortmaßnahmen

1. Perimeter-Inspektion: Relevante Portfreigaben und exponierte Endpunkte unverzüglich scannen.
2. Patch-Applikation: Hersteller-Hotfix einspielen oder betroffene Daemons in isolierte DMZ-Segmente überführen.
3. Telemetrie & EDR-Alerts: Prozessaufrufe und Child-Processes auf anomale Shell-Spawns überwachen.

🔗 Semantisch verwandte Zero-Days MariaDB 11.7 VEC

Schnell-Prompts für Analysten

⚠️ DEFANGED SANDBOX VIEW (tsecurity.de): Alle Netzwerkindikatoren und URLs wurden neutralisiert (2 Indikatoren entschärft). Nur zur defensiven Analyse!

Format: python

#!/usr/bin/env python3
# Exploit Title: PoC for Target
import socket, sys
target = '192[.]168[.]1[.]10'
url = 'hxxp://target[.]local/vuln'
s = socket.socket()
s.connect((target, 80))
s.send(b'GET / HTTP/1.1\r\nHost: target.local\r\n\r\n')