CVE-2025-36582: Dell Networker Information Disclosure Flaw

CVE-2025-36582 Overview

CVE-2025-36582 is an Algorithm Downgrade vulnerability affecting Dell NetWorker, a widely deployed enterprise backup and recovery solution. The vulnerability exists in the cryptographic negotiation process, where an attacker can force the system to select a weaker, less secure algorithm during communication establishment. This flaw allows unauthenticated remote attackers to potentially expose sensitive information by exploiting the weakened encryption.

Critical Impact

Unauthenticated remote attackers can exploit this algorithm downgrade vulnerability to disclose sensitive information from Dell NetWorker deployments, potentially compromising backup data and credentials.

Affected Products

• Dell NetWorker versions 19.12.0.1 and prior
• Dell NetWorker enterprise backup and recovery solutions
• Environments utilizing Dell NetWorker for data protection

Discovery Timeline

• 2025-07-01 - CVE-2025-36582 published to NVD
• 2025-08-14 - Last updated in NVD database

Technical Details for CVE-2025-36582

Vulnerability Analysis

This vulnerability falls under CWE-757 (Selection of Less-Secure Algorithm During Negotiation), commonly referred to as an algorithm downgrade attack. During the cryptographic handshake process between Dell NetWorker components or between the NetWorker server and clients, the negotiation mechanism fails to properly enforce the use of strong cryptographic algorithms. An attacker positioned on the network can manipulate this negotiation to force the selection of weaker algorithms that are more susceptible to cryptographic attacks.

The vulnerability is exploitable remotely without requiring authentication, making it particularly concerning for organizations with NetWorker deployments exposed to untrusted networks. The primary impact is information disclosure, where attackers could potentially intercept and decrypt communications containing sensitive backup data, credentials, or configuration information.

Root Cause

The root cause of CVE-2025-36582 lies in the improper implementation of cryptographic algorithm negotiation within Dell NetWorker. The application fails to enforce a minimum security standard during the TLS or encryption negotiation phase, allowing legacy or deprecated algorithms to be selected when stronger options should be mandated. This design flaw enables man-in-the-middle attackers to inject themselves into the negotiation process and artificially constrain the algorithm choices to weaker options.

Attack Vector

The attack vector is network-based, requiring no authentication or user interaction. An attacker with network access to Dell NetWorker communications can perform the following attack sequence:

1. Position themselves to intercept network traffic between NetWorker components
2. Intercept the cryptographic negotiation handshake
3. Manipulate the handshake to remove or deprioritize strong algorithms
4. Force the connection to use a weaker algorithm susceptible to cryptanalysis
5. Decrypt intercepted communications to extract sensitive information

The vulnerability mechanism exploits the fallback behavior in Dell NetWorker's encryption negotiation. When stronger algorithms are artificially removed from the negotiation, the system accepts weaker alternatives rather than failing closed. For detailed technical information, refer to the Dell Security Update DSA-2025-268.

Detection Methods for CVE-2025-36582

Indicators of Compromise

• Unexpected use of deprecated or weak cipher suites in NetWorker communications
• TLS/SSL connections using algorithms like RC4, DES, or export-grade ciphers
• Unusual network traffic patterns during backup or recovery operations
• Evidence of man-in-the-middle positioning on network segments containing NetWorker infrastructure

Detection Strategies

• Monitor TLS handshake negotiations for algorithm downgrade patterns using network traffic analysis
• Configure SIEM rules to alert on connections utilizing weak or deprecated cipher suites
• Implement deep packet inspection to identify suspicious negotiation manipulation attempts
• Audit Dell NetWorker logs for unusual connection behaviors or authentication anomalies

Monitoring Recommendations

• Enable comprehensive logging for all Dell NetWorker communications and authentication events
• Deploy network monitoring solutions to baseline and alert on cryptographic algorithm usage
• Implement endpoint detection on NetWorker servers to identify potential exploitation attempts
• Regularly review SSL/TLS certificate configurations and enforce strong cipher suite policies

How to Mitigate CVE-2025-36582

Immediate Actions Required

• Review the Dell Security Update DSA-2025-268 and apply the recommended security patch
• Audit current Dell NetWorker version deployments to identify vulnerable instances running version 19.12.0.1 or prior
• Restrict network access to Dell NetWorker infrastructure to trusted networks and IP ranges
• Implement network segmentation to isolate backup infrastructure from general network traffic

Patch Information

Dell has released a security update to address this vulnerability. Organizations should immediately consult the Dell Security Update DSA-2025-268 for specific patch details and upgrade instructions. The patch enforces proper algorithm selection during cryptographic negotiation, preventing downgrade attacks.

Workarounds

• Configure firewalls and network ACLs to restrict access to NetWorker services to authorized hosts only
• Implement VPN or IPsec tunnels for NetWorker communications across untrusted networks
• Disable legacy cipher suites at the operating system or network level where possible
• Consider deploying a TLS termination proxy with strict cipher suite enforcement in front of NetWorker services

# Configuration example - Restrict network access to NetWorker services
# Add firewall rules to limit access to NetWorker ports
iptables -A INPUT -p tcp --dport 7937:7940 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 7937:7940 -j DROP