CVE-2024-31878
📋 TL;DR
IBM i Service Tools Server (SST) versions 7.2 through 7.5 are vulnerable to user enumeration by remote attackers. This allows malicious actors to identify valid SST user accounts, which can then be targeted for credential attacks or other exploitation. The vulnerability affects IBM i operating systems with SST enabled.
💻 Affected Systems
- IBM i Service Tools Server (SST)
📦 What is this software?
I by Ibm
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⚠️ Risk & Real-World Impact
Worst Case
Attackers identify all SST users, perform credential attacks to gain unauthorized access, then use SST privileges to compromise the IBM i system or pivot to other systems.
Likely Case
Attackers enumerate SST users and use the information for targeted phishing, credential stuffing, or brute force attacks against identified accounts.
If Mitigated
Attackers can identify user accounts but cannot gain access due to strong authentication controls, monitoring, and network restrictions.
🎯 Exploit Status
User enumeration typically requires minimal technical skill. No public exploit code is known, but the technique is well-understood.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Apply IBM i PTF groups as specified in IBM advisory
Vendor Advisory: https://www.ibm.com/support/pages/node/7156725
Restart Required: Yes
Instructions:
1. Review IBM advisory 7156725 for specific PTF requirements. 2. Apply required PTF groups for your IBM i version. 3. Restart affected services or the entire system as required.
🔧 Temporary Workarounds
Restrict SST Network Access
allConfigure firewall rules to restrict SST access to trusted networks only.
Configure IBM i firewall or external firewall to block unauthorized access to SST ports (typically 2001-2005)
Disable SST If Not Required
ibmiDisable the Service Tools Server if not needed for operations.
STRTCPSVR SERVER(*SST) to start, ENDTCPSVR SERVER(*SST) to stop
🧯 If You Can't Patch
- Implement network segmentation to isolate SST servers from untrusted networks.
- Enable multi-factor authentication for all SST users and implement account lockout policies.
🔍 How to Verify
Check if Vulnerable:
Check if SST is running and accessible from untrusted networks. Test if user enumeration is possible via SST authentication mechanisms.Check Version:
DSPPTF to check installed PTFs, or GO LICPGM to check IBM i versionVerify Fix Applied:
Verify PTF groups are applied using WRKPTFGRP command and test that user enumeration no longer works.📡 Detection & Monitoring
Log Indicators:
- Multiple failed authentication attempts against SST from single source
- Unusual SST connection patterns or from unexpected IP addresses
Network Indicators:
- Traffic to SST ports (2001-2005) from unauthorized sources
- Patterns of authentication requests with varying usernames
SIEM Query:
source_port:2001-2005 AND (event_type:authentication_failure OR event_type:connection_attempt) | stats count by src_ip