Overview
CVE-2021-4467 describes a remote denial-of-service (DoS) vulnerability affecting Positive Technologies MaxPatrol 8 and XSpider. This vulnerability resides within the client communication service, specifically on TCP port 2002. An attacker can exploit this flaw by overwhelming the service with connection requests, leading to service disruption.
Technical Details
The vulnerability stems from the service’s inadequate handling of incoming connection requests. For each new connection, the service generates a new session identifier. However, there is no proper limitation on the number of concurrent requests it can handle. An unauthenticated remote attacker can exploit this by repeatedly sending HTTPS requests to the service. This action causes the excessive allocation of session identifiers, consuming server resources. Under a heavy load, session identifier collisions are likely to occur. When this happens, active client sessions are forcibly disconnected, effectively causing a denial of service.
CVSS Analysis
Currently, the CVE record indicates that a CVSS score and severity are not available. However, given the potential for denial of service, it is advisable to treat this vulnerability with appropriate concern. While the lack of CVSS score makes precise risk assessment difficult, consider it as potentially high if your MaxPatrol 8 or XSpider deployment is publicly accessible.
Possible Impact
The successful exploitation of CVE-2021-4467 can lead to the following consequences:
- Service Disruption: Legitimate users will be unable to access MaxPatrol 8 or XSpider services due to resource exhaustion.
- Loss of Monitoring Capabilities: The denial of service can halt critical security monitoring functions.
- Potential Security Blind Spot: While the service is down, other security incidents may go unnoticed.
Mitigation or Patch Steps
To mitigate the risk posed by CVE-2021-4467, the following steps are recommended:
- Contact Positive Technologies: Reach out to Positive Technologies directly for the latest patches or security advisories related to this vulnerability.
- Implement Rate Limiting: If possible, implement rate limiting on TCP port 2002 to restrict the number of incoming connections from a single IP address within a specific timeframe.
- Network Segmentation: Isolate the MaxPatrol 8 and XSpider services within a segmented network to limit the attack surface.
- Monitor for Anomalous Activity: Continuously monitor network traffic for unusual patterns that could indicate an ongoing denial-of-service attack.
- Web Application Firewall (WAF): Consider deploying a Web Application Firewall (WAF) that can detect and block malicious requests targeting the vulnerable service.
