CVE-2025-21601

CVE-2025-21601: Improper Following of Specification by Caller in Junos OS Web Management

Description:

An Improper Following of Specification by Caller vulnerability exists in the web management interfaces (J-Web, Captive Portal, 802.1X, Juniper Secure Connect (JSC)) of Juniper Networks Junos OS on SRX Series, EX Series, MX240, MX480, MX960, QFX5120 Series. An unauthenticated, network-based attacker can send legitimate traffic targeted to the device, causing the CPU utilization to spike until the device becomes unresponsive, leading to a sustained Denial of Service (DoS) condition.

Severity:

  • CVSS Score: 8.7 (High)

Known Exploit:

  • An unauthenticated, network-based attacker can exploit this vulnerability by sending genuine traffic specifically crafted to trigger the vulnerability. The continuous receipt of these packets will cause a sustained Denial of Service (DoS) condition, rendering the device unresponsive.

Affected Versions:

  • Junos OS versions before 21.4R3-S9
  • Junos OS 22.2 before 22.2R3-S5
  • Junos OS 22.4 before 22.4R3-S4
  • Junos OS 23.2 before 23.2R2-S3
  • Junos OS 23.4 before 23.4R2-S3
  • Junos OS 24.2 before 24.2R1-S1, 24.2R2

Remediation/Mitigation Strategy:

  1. Upgrade Junos OS: The primary remediation is to upgrade to a fixed version of Junos OS:

    • 21.4R3-S9 or later
    • 22.2R3-S5 or later
    • 22.4R3-S4 or later
    • 23.2R2-S3 or later
    • 23.4R2-S3 or later
    • 24.2R1-S1 or 24.2R2 or later (preferably a later release like 24.2R3)

  2. Monitor CPU Usage: Regularly monitor the CPU usage of the httpd process on affected devices. Elevated and sustained CPU utilization (e.g., 80% or higher) of the httpd process may indicate an active exploit.

    show system processes extensive | match httpd

  3. Rate Limiting (If feasible): Implement rate limiting or traffic shaping policies on the network perimeter or within the device’s firewall configuration to limit the rate of incoming traffic to the affected web management interfaces. This can help mitigate the impact of a DoS attack by preventing the device from being overwhelmed. However, proper configuration is crucial to avoid blocking legitimate traffic.

  4. Access Control Lists (ACLs) (If feasible): Restrict access to the web management interfaces (J-Web, Captive Portal, 802.1X, Juniper Secure Connect (JSC)) by using Access Control Lists (ACLs) to allow only authorized administrative IP addresses to connect. If remote access is required, consider using a VPN or other secure tunneling mechanism.

  5. Disable Unnecessary Services (If feasible): If the web management interfaces (J-Web, Captive Portal, 802.1X, Juniper Secure Connect (JSC)) are not required, consider disabling them to reduce the attack surface. Be aware of the impact to services dependent on these interfaces before disabling.

  6. Intrusion Detection/Prevention Systems (IDS/IPS): Deploy and configure intrusion detection/prevention systems (IDS/IPS) to detect and block malicious traffic patterns associated with this vulnerability. Ensure the IDS/IPS signatures are up-to-date.

  7. Security Information and Event Management (SIEM): Integrate device logs with a SIEM system to facilitate centralized monitoring and analysis. Configure alerts to notify security personnel of suspicious activity or high CPU utilization related to the httpd process.

  8. Vendor Communication: Stay informed about security advisories and updates from Juniper Networks regarding this vulnerability and related threats.

Note: Applying these mitigation strategies can reduce the risk associated with this vulnerability, but the most effective solution is to upgrade to a patched version of Junos OS. Evaluate each mitigation in your environment to ensure it aligns with business and operational requirements.

Assigner

Date

  • Published Date: 2025-04-09 20:15:26
  • Updated Date: 2025-04-09 20:15:26

More Details

CVE-2025-21601