CVE-2024-41743 Overview
CVE-2024-41743 affects IBM TXSeries for Multiplatforms 10.1, a transaction processing environment for distributed CICS applications. A remote attacker can trigger a denial of service (DoS) condition by abusing persistent connections that the server fails to allocate resources for correctly. The flaw is tracked under CWE-770: Allocation of Resources Without Limits or Throttling. Exploitation requires no authentication and no user interaction, and the network attack vector makes the issue reachable from any client that can establish a TCP session to the service.
Critical Impact
An unauthenticated remote attacker can exhaust server resources through persistent connections, rendering IBM TXSeries for Multiplatforms 10.1 unavailable to legitimate transaction processing workloads.
Affected Products
- IBM TXSeries for Multiplatforms 10.1
- Deployments on supported Linux platforms
- Distributed CICS application environments using TXSeries persistent connection handling
Discovery Timeline
- 2025-01-19 - CVE-2024-41743 published to the National Vulnerability Database
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2024-41743
Vulnerability Analysis
The vulnerability resides in how IBM TXSeries for Multiplatforms 10.1 manages persistent network connections. The server accepts and retains client connections without enforcing sufficient limits or throttling on the resources each connection consumes. An unauthenticated attacker can open and hold many persistent sessions, progressively consuming sockets, memory, threads, or file descriptors until the service degrades or stops responding.
The CWE-770 classification indicates a missing upper bound on resource allocation. Because TXSeries supports long-lived sessions for transaction processing clients, the absence of proper allocation controls allows a small number of attacker-controlled hosts to deny service to legitimate CICS applications. The EPSS score of 0.605% reflects current observed exploitation likelihood, though the low attack complexity makes opportunistic abuse straightforward.
Root Cause
The root cause is improper allocation of resources during persistent connection handling. TXSeries does not adequately cap concurrent persistent sessions per source, per process, or in aggregate. Connections that should be reclaimed or rate-limited instead accumulate and tie up server-side resources required by other transactions.
Attack Vector
Attackers reach the vulnerability across the network without credentials or user interaction. By repeatedly establishing TCP sessions and keeping them alive against the TXSeries listener, the attacker forces the server to allocate per-connection state until limits are reached. Exploitation does not compromise confidentiality or integrity but produces a high-impact availability outcome, consistent with the CVSS vector's A:H component.
No public proof-of-concept exploit is referenced for CVE-2024-41743, and the issue is not listed in the CISA Known Exploited Vulnerabilities catalog. Detailed remediation guidance is provided in the IBM Support Document.
Detection Methods for CVE-2024-41743
Indicators of Compromise
- Sudden growth in the number of established TCP sessions to TXSeries listener ports from a small set of source addresses
- TXSeries processes reporting elevated thread, socket, or file descriptor usage without a matching increase in completed transactions
- Legitimate CICS clients receiving connection timeouts or refused connections during normal operating hours
- Operating system logs showing EMFILE or ENOMEM errors associated with TXSeries processes
Detection Strategies
- Baseline normal concurrent connection counts and alert on deviations exceeding expected peaks
- Correlate connection counts per source IP with transaction throughput to identify connections that consume resources without performing work
- Inspect long-lived idle sessions whose duration substantially exceeds typical client behavior
Monitoring Recommendations
- Continuously monitor TXSeries process resource consumption, including thread count, memory, and open file descriptors
- Forward TXSeries and operating system logs to a centralized analytics platform for correlation across hosts
- Track connection establishment rates at the network perimeter and on the TXSeries host using flow telemetry
How to Mitigate CVE-2024-41743
Immediate Actions Required
- Apply the fix referenced in the IBM Support Document for CVE-2024-41743 on all TXSeries for Multiplatforms 10.1 hosts
- Restrict network access to TXSeries listener ports to known client subnets using host firewalls or network ACLs
- Place rate limits and connection caps in front of TXSeries using a reverse proxy or load balancer where feasible
- Review and reduce idle connection timeouts so abandoned sessions are reclaimed promptly
Patch Information
IBM has published remediation guidance for CVE-2024-41743 in the official advisory. Administrators should follow the version and fix pack instructions in the IBM Support Document for TXSeries for Multiplatforms 10.1 and validate the fix in a non-production environment before rolling out broadly.
Workarounds
- Enforce per-source connection limits with stateful firewalls or load balancers until patches are applied
- Lower keep-alive and idle timeout values for TXSeries listeners to reclaim resources from abandoned sessions
- Segment TXSeries hosts so that only authorized application tiers can initiate persistent connections
# Example: limit concurrent connections per source IP to the TXSeries listener using iptables
# Replace <PORT> with the TXSeries listener port and tune the connlimit value to your environment.
iptables -A INPUT -p tcp --syn --dport <PORT> \
-m connlimit --connlimit-above 20 --connlimit-mask 32 -j REJECT --reject-with tcp-reset
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
