CVE-2025-33084: IBM Concert Information Disclosure Flaw

CVE-2025-33084 Overview

CVE-2025-33084 affects IBM Concert Software versions 1.0.0 through 1.1.0. The product fails to properly enable HTTP Strict Transport Security (HSTS), a mechanism designed to force browsers into HTTPS-only communication with the server. A remote attacker positioned on the network path can exploit this weakness through man-in-the-middle (MITM) techniques to intercept or downgrade traffic and obtain sensitive information. The issue is tracked under CWE-327: Use of a Broken or Risky Cryptographic Algorithm, reflecting weakness in transport-layer protection guarantees.

Critical Impact
Missing HSTS enforcement allows attackers to strip TLS protection and intercept confidential data exchanged with IBM Concert.

Affected Products

IBM Concert Software 1.0.0
IBM Concert Software 1.0.x
IBM Concert Software up to and including 1.1.0

Discovery Timeline

2025-09-01 - CVE-2025-33084 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-33084

Vulnerability Analysis

IBM Concert Software does not send the Strict-Transport-Security response header on HTTPS responses. Without this header, browsers have no policy instructing them to only connect over HTTPS on subsequent visits. An attacker with network position between the user and the Concert application can intercept the initial plaintext request and prevent an upgrade to TLS. The vulnerability requires high attack complexity because the attacker must control a network path such as public Wi-Fi, a compromised router, or an ARP-spoofed segment. Successful exploitation exposes session cookies, authentication tokens, and application data submitted to the Concert interface.

Root Cause

The root cause is a missing security control at the HTTP layer. IBM Concert releases 1.0.0 through 1.1.0 do not configure the web tier to emit Strict-Transport-Security with a max-age directive. Without HSTS, TLS enforcement depends entirely on user behavior and network integrity. This design gap falls under insecure communication configuration and is classified as a cryptographic weakness because it undermines the confidentiality guarantees of TLS in practice.

Attack Vector

The attack is conducted over the network without authentication or user interaction. A typical exploitation flow uses an SSL-stripping proxy such as sslstrip or bettercap on the same broadcast domain as the victim. The attacker rewrites HTTPS links to HTTP in intercepted responses and proxies plaintext traffic to the legitimate Concert endpoint. Because the browser was never instructed to require HTTPS, it follows the downgraded links and transmits credentials or session identifiers in cleartext. The attacker records this traffic and reuses the tokens to access sensitive information within the Concert application.

Refer to the IBM Support Page for vendor technical details.

Detection Methods for CVE-2025-33084

Indicators of Compromise

HTTP responses from IBM Concert endpoints that do not contain a Strict-Transport-Security header.
Unexpected plaintext HTTP sessions to Concert hostnames that historically served HTTPS only.
ARP table anomalies or duplicate MAC entries on subnets where Concert clients operate.
Session tokens for Concert observed in network captures without TLS encapsulation.

Detection Strategies

Run automated HTTP header scanners such as curl -I or testssl.sh against Concert endpoints to confirm HSTS presence.
Correlate proxy or web gateway logs for HTTP (port 80) traffic destined for Concert hostnames.
Inspect network flow data for TLS downgrade patterns preceding authentication events.

Monitoring Recommendations

Alert on any client-to-Concert connection that completes over HTTP instead of HTTPS.
Monitor DNS and ARP integrity on subnets hosting Concert users to catch MITM staging activity.
Track response headers from Concert in synthetic monitoring to detect regressions after patching.

How to Mitigate CVE-2025-33084

Immediate Actions Required

Apply the fix referenced in the IBM Support advisory for IBM Concert.
Restrict Concert access to trusted networks or require VPN termination for remote users until patched.
Rotate session cookies, API tokens, and administrative credentials that may have transited untrusted networks.

Patch Information

IBM has published guidance for CVE-2025-33084 on the IBM Support Page. Upgrade IBM Concert to the fixed release specified by IBM. Versions 1.0.0 through 1.1.0 are affected and should be considered vulnerable until the vendor-provided update is applied.

Workarounds

Enforce HSTS at an upstream reverse proxy or load balancer fronting Concert by adding the Strict-Transport-Security header with a suitable max-age.
Disable HTTP listeners entirely and require HTTPS on the Concert service and its ingress components.
Preload the Concert hostname into the browser HSTS preload list once HTTPS-only operation is confirmed.

bash

# Example: enforce HSTS at an NGINX reverse proxy in front of IBM Concert
server {
    listen 443 ssl http2;
    server_name concert.example.com;

    add_header Strict-Transport-Security "max-age=31536000; includeSubDomains; preload" always;

    location / {
        proxy_pass https://concert-backend.internal;
        proxy_set_header Host $host;
        proxy_set_header X-Forwarded-Proto https;
    }
}

server {
    listen 80;
    server_name concert.example.com;
    return 301 https://$host$request_uri;
}