CVE-2023-35871
📋 TL;DR
CVE-2023-35871 is a memory corruption vulnerability in SAP Web Dispatcher and related components that allows unauthenticated attackers to cause logical errors in memory management. This can lead to information disclosure or system crashes, primarily affecting system integrity and availability. Organizations running affected SAP Web Dispatcher versions are vulnerable.
💻 Affected Systems
- SAP Web Dispatcher
- SAP Kernel
- SAP HANA Database
- SAP Extended Application Services
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system crash leading to denial of service, potential memory corruption allowing arbitrary code execution, and information disclosure from memory contents.
Likely Case
System crashes and denial of service affecting SAP application availability, with possible information leakage from memory.
If Mitigated
Limited impact with proper network segmentation and access controls preventing unauthenticated access to vulnerable components.
🎯 Exploit Status
Exploitation requires understanding of SAP memory management and crafting specific requests, but unauthenticated access lowers the barrier.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Apply SAP Note 3340735 patches for respective versions
Vendor Advisory: https://me.sap.com/notes/3340735
Restart Required: Yes
Instructions:
1. Download patches from SAP Support Portal using Note 3340735. 2. Apply patches to affected SAP Web Dispatcher and Kernel components. 3. Restart SAP Web Dispatcher services. 4. Verify patch application using version checks.
🔧 Temporary Workarounds
Network Segmentation
allRestrict network access to SAP Web Dispatcher to only trusted sources
# Example firewall rule (Linux iptables): iptables -A INPUT -p tcp --dport 80,443 -s trusted_network -j ACCEPT
# Example firewall rule (Windows): New-NetFirewallRule -DisplayName 'SAP Web Dispatcher Access' -Direction Inbound -Protocol TCP -LocalPort 80,443 -RemoteAddress trusted_network -Action Allow
Load Balancer Protection
allPlace Web Application Firewall (WAF) or load balancer in front of SAP Web Dispatcher
# Configure WAF rules to filter suspicious requests
# Example mod_security rule: SecRule REQUEST_URI "@rx suspicious_pattern" "id:1001,phase:2,deny"
🧯 If You Can't Patch
- Implement strict network access controls to limit exposure to SAP Web Dispatcher
- Deploy intrusion detection systems to monitor for exploitation attempts and memory corruption patterns
🔍 How to Verify
Check if Vulnerable:
Check SAP Web Dispatcher and Kernel version numbers against affected versions list. Review system logs for memory corruption errors or crashes.Check Version:
# On SAP system: dpmon or sapcontrol -function GetVersionVerify Fix Applied:
Verify SAP Note 3340735 has been applied through SAP transaction SNOTE or by checking patch status in SAP system.📡 Detection & Monitoring
Log Indicators:
- Memory allocation errors in SAP system logs
- Web Dispatcher crash dumps
- Unexpected process terminations
- High memory usage spikes
Network Indicators:
- Unusual traffic patterns to SAP Web Dispatcher ports
- Requests causing abnormal memory allocation
- Connection attempts from unexpected sources
SIEM Query:
source="sap_logs" AND ("memory corruption" OR "segmentation fault" OR "access violation") OR destination_port IN (80, 443, 81XX) AND protocol="TCP" AND bytes_sent>threshold