CVE-2024-53702: SonicWall SMA 200 PRNG Vulnerability

CVE-2024-53702 Overview

CVE-2024-53702 is an insecure random number generation vulnerability affecting the SonicWall SMA100 SSLVPN backup code generator. The vulnerability stems from the use of a cryptographically weak pseudo-random number generator (PRNG) that, under certain conditions, allows attackers to predict the generated values. This predictability can lead to the exposure of generated secrets used in the backup process, potentially compromising the security of backup operations and associated authentication mechanisms.

Critical Impact

Attackers capable of predicting the weak PRNG output could potentially gain access to backup codes, enabling unauthorized access to SSLVPN backup functionality and potentially exposing sensitive configuration data.

Affected Products

• SonicWall SMA 200 Firmware
• SonicWall SMA 210 Firmware
• SonicWall SMA 400 Firmware
• SonicWall SMA 410 Firmware
• SonicWall SMA 500v Firmware

Discovery Timeline

• December 5, 2024 - CVE-2024-53702 published to NVD
• November 4, 2025 - Last updated in NVD database

Technical Details for CVE-2024-53702

Vulnerability Analysis

The vulnerability exists within the backup code generation mechanism of the SonicWall SMA100 SSLVPN implementation. The core issue is the reliance on a cryptographically weak pseudo-random number generator (CWE-338) for generating backup codes that should be unpredictable. When a PRNG lacks sufficient entropy or uses a predictable algorithm, attackers with knowledge of the generation mechanism can potentially reconstruct or predict the sequence of generated values.

In the context of SSLVPN appliances, backup codes serve as critical security tokens that may be used for account recovery or secondary authentication purposes. The compromise of these codes could allow an attacker to bypass authentication mechanisms or gain unauthorized access to VPN backup functionality.

Root Cause

The root cause of this vulnerability is the improper implementation of random number generation for security-critical operations. The backup code generator uses a PRNG algorithm that does not meet cryptographic security standards, making it susceptible to prediction attacks. Cryptographically secure PRNGs (CSPRNGs) should be used for any security-sensitive random number generation, particularly for authentication tokens, backup codes, and session identifiers.

Attack Vector

The attack vector is network-based, allowing remote exploitation without authentication. An attacker can potentially exploit this vulnerability by:

1. Observing or gathering information about the backup code generation process
2. Analyzing the weak PRNG implementation to understand its predictability patterns
3. Predicting future or past backup codes based on the PRNG state
4. Using the predicted codes to gain unauthorized access to backup functionality

The vulnerability requires no user interaction and can be exploited remotely, though successful exploitation depends on the attacker's ability to analyze and predict the PRNG output under specific conditions.

Detection Methods for CVE-2024-53702

Indicators of Compromise

• Unusual or repeated backup code generation requests from unexpected sources
• Multiple failed authentication attempts using backup codes followed by successful access
• Anomalous access patterns to SSLVPN management interfaces from external IP addresses
• Log entries showing backup functionality access from unauthorized users or at unusual times

Detection Strategies

• Monitor SMA100 appliance logs for excessive backup code generation or validation attempts
• Implement alerting for any backup-related operations performed outside of scheduled maintenance windows
• Deploy network-based anomaly detection to identify reconnaissance activities targeting the SSLVPN interface
• Review authentication logs for patterns suggesting brute-force attempts against backup code mechanisms

Monitoring Recommendations

• Enable comprehensive logging on all SonicWall SMA100 devices and forward logs to a centralized SIEM
• Configure alerts for backup functionality access and any administrative operations
• Regularly audit backup code usage and investigate any unexpected activity
• Implement network traffic analysis to detect potential PRNG analysis attempts

How to Mitigate CVE-2024-53702

Immediate Actions Required

• Apply the latest firmware update from SonicWall that addresses this vulnerability
• Review and restrict access to backup functionality to only authorized administrators
• Implement additional authentication controls where possible for backup operations
• Audit existing backup codes and regenerate them after applying the patch

Patch Information

SonicWall has released a security advisory addressing this vulnerability. Administrators should consult the SonicWall Vulnerability Advisory SNWLID-2024-0018 for specific patch versions and upgrade instructions. It is strongly recommended to update all affected SMA100 series devices to the latest available firmware version that contains the fix for this vulnerability.

Workarounds

• Restrict network access to the SMA100 management interface using firewall rules or ACLs
• Disable backup code functionality if not required for operations until patching can be completed
• Implement IP allowlisting to limit which addresses can access SSLVPN administrative functions
• Enable multi-factor authentication for all administrative access to add an additional layer of security