# Critical Vulnerability in Cisco Product Allows Unauthorized Access

## **Details**

Cisco has just issued a warning about a critical vulnerability – CVE-2025-20309 – affecting Cisco Unified Communications Manager (Unified CM) and Unified CM Session Management Edition (SME). This vulnerability allows an unauthenticated attacker to access the system with root privileges through a default account that is hardcoded and cannot be changed or deleted.

* **CVE Code:** CVE-2025-20309
    
* **Severity Level:** **High Risk (CVSS v3: 10)**
    
* **Impact:** Allows a remote attacker without authentication to log into the system with **root** privileges through the SSH port.
    
* ![](https://cdn.hashnode.com/res/hashnode/image/upload/v1751947821389/96ea9225-7a25-4c80-be4b-99088c0093b8.png?auto=compress,format&format=webp align="left")
    

### **Affected Products**

* Cisco Unified CM and Unified CM SME Engineering Special (ES) versions from 15.0.1.13010-1 to 15.0.1.13017-1 are affected.
    

| **Cisco Unified CM & SME Release** | **Fixed Version** |
| --- | --- |
| 12.5 | Not vulnerable |
| 14 | Not vulnerable |
| 15.0.1.13010-1 → 13017-1 | 15SU3 (07/2025) or apply patch: `ciscocm.CSCwp27755_D0247-1.cop.sha512` |

---

### **Exploitation Potential and Indicators of Compromise (IoC)**

This vulnerability allows an attacker to:

* Access the system with **root privileges**
    
* Install malware and gain unauthorized access to sensitive data
    
* Move laterally to expand the attack within the internal system
    

Indicators of Compromise (IoC) include log records showing successful SSH login using the root account in the file `/var/log/active/syslog/secure`. Cisco advises customers to check their systems using the following CLI command:

* ```csharp
        file get activelog syslog/secure
    ```
    
* Successful exploitation will be recorded in the file `/var/log/active/syslog/secure` with an SSH login from the `root` user.
    
* Example log indicating an Indicator of Compromise (IoC):
    
    ```csharp
      Apr 6 10:38:43 xxx authpriv 6 sshd: pam_unix(sshd:session): session opened for user root by (uid=0)
    ```
    

---

## **Recommendations**

**FPT Threat Intelligence** urgently recommends the following measures to address the vulnerability:

1. **Update the patch immediately:**
    
    * Cisco has released an update to fix the affected products.
        
    * Visit the [**Cisco Security Advisory**](https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-cucm-ssh-m4UBdpE7) page to download the appropriate patch.
        
2. **Check and monitor SSH connections:**
    
    * Review unusual SSH connections to the device.
        
    * Ensure there is no unauthorized access using static accounts.
        
3. **Disable SSH if not in use:**
    
    * For systems that do not require SSH, disable it to reduce the attack surface.
        
4. **Reevaluate account management policies:**
    
    * Avoid using hardcoded accounts.
        
    * Use strong authentication (multi-factor authentication) if possible.
        
5. **Enhance log monitoring and alerts:**
    
    * Connect the system to SIEM to track unusual behavior.
        
    * Set up alerts for root access via SSH.
        

---

### **References**

* [**Cisco Advisory: CVE-2024-20253**](https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-cucm-ssh-m4UBdpE7)
    
* [**Static Credentials Flaw Patched in Cisco Systems**](https://www.databreachtoday.com/static-credentials-flaw-patched-in-cisco-systems-a-28899)