CVE-2025-33090: IBM Concert DoS Vulnerability

CVE-2025-33090 Overview

IBM Concert Software versions 1.0.0 through 1.1.0 contain a Regular Expression Denial of Service (ReDoS) vulnerability that could allow a remote attacker to cause a denial of service. By crafting a specially designed regular expression input, an attacker can trigger excessive resource consumption on the target system, potentially rendering the application unresponsive.

Critical Impact

Remote attackers can exploit this ReDoS vulnerability without authentication to exhaust server resources and cause service disruption for IBM Concert Software deployments.

Affected Products

• IBM Concert Software 1.0.0
• IBM Concert Software 1.0.1 through 1.0.x
• IBM Concert Software 1.1.0

Discovery Timeline

• 2025-08-18 - CVE-2025-33090 published to NVD
• 2025-08-21 - Last updated in NVD database

Technical Details for CVE-2025-33090

Vulnerability Analysis

This vulnerability is classified under CWE-1333 (Inefficient Regular Expression Complexity), commonly known as Regular Expression Denial of Service (ReDoS). The flaw exists in how IBM Concert Software processes regular expression patterns, where certain malformed or deliberately crafted input strings can cause the regex engine to enter a state of catastrophic backtracking.

When a vulnerable regular expression encounters specially crafted input, the regex engine may attempt an exponential number of matching operations. This algorithmic complexity attack causes CPU utilization to spike dramatically, consuming server resources and potentially leading to service unavailability for legitimate users.

The network-accessible nature of this vulnerability means that remote attackers can exploit it without requiring any prior authentication or user interaction, making it particularly concerning for internet-facing deployments of IBM Concert Software.

Root Cause

The root cause lies in inefficient regular expression patterns within IBM Concert Software that are susceptible to catastrophic backtracking. Certain regex constructs, such as nested quantifiers or overlapping alternations, can cause the regex matching algorithm to explore an exponentially growing number of possible match paths when presented with adversarial input strings.

Attack Vector

This vulnerability can be exploited remotely over the network. An attacker can send maliciously crafted input containing specially designed strings to endpoints where IBM Concert Software performs regular expression processing. The attack requires no privileges or authentication, and no user interaction is necessary. The exploitation targets system availability by exhausting CPU resources during regex evaluation.

The attack typically involves identifying input fields or API endpoints that process user-supplied data through regular expressions, then submitting input strings designed to maximize backtracking iterations in the vulnerable regex patterns.

Detection Methods for CVE-2025-33090

Indicators of Compromise

• Sudden and sustained spikes in CPU utilization on servers running IBM Concert Software
• Degraded application response times or complete service unavailability
• Unusual request patterns with abnormally long or repetitive string inputs
• Increased memory consumption associated with regex processing threads

Detection Strategies

• Monitor server CPU and memory utilization for anomalous sustained spikes during normal operation periods
• Implement request logging and analyze for patterns of inputs containing repetitive character sequences
• Deploy Web Application Firewall (WAF) rules to detect and block ReDoS attack patterns
• Use application performance monitoring tools to identify slow regex processing operations

Monitoring Recommendations

• Configure alerting thresholds for CPU utilization exceeding normal operational baselines
• Implement request timeout monitoring to detect hanging or excessively long-running requests
• Enable detailed logging for input validation and regex processing components
• Establish baseline performance metrics to quickly identify deviations indicative of DoS attacks

How to Mitigate CVE-2025-33090

Immediate Actions Required

• Apply the security patch provided by IBM as outlined in the vendor advisory
• Upgrade IBM Concert Software to a patched version beyond 1.1.0
• Implement input length restrictions and validation on all user-supplied input fields
• Consider deploying rate limiting to reduce the impact of potential exploitation attempts

Patch Information

IBM has released a security advisory addressing this vulnerability. Organizations running IBM Concert Software versions 1.0.0 through 1.1.0 should consult the IBM Security Bulletin for detailed patching instructions and updated software downloads.

Workarounds

• Implement input validation to restrict the length and character composition of user-supplied strings before regex processing
• Deploy a Web Application Firewall (WAF) with ReDoS protection rules in front of IBM Concert Software
• Configure request timeouts at the application and web server level to terminate long-running regex operations
• Consider implementing regex execution timeouts or safe regex libraries that prevent catastrophic backtracking

# Example: Configure request timeout at web server level
# For Apache httpd
Timeout 30
RequestReadTimeout header=20-40,MinRate=500 body=20,MinRate=500

# For nginx
client_body_timeout 30s;
client_header_timeout 30s;
send_timeout 30s;