CVE-2023-43119: Extremenetworks EXOS Privilege Escalation

CVE-2023-43119 Overview

CVE-2023-43119 is a critical access control vulnerability discovered in Extreme Networks Switch Engine (EXOS). The flaw allows remote attackers to gain escalated privileges by exploiting improper access controls via crafted telnet commands targeting the Redis server component. This vulnerability affects network infrastructure devices and poses significant risk to enterprise network environments where EXOS-based switches are deployed.

Critical Impact

Remote attackers can achieve privilege escalation on affected Extreme Networks switches through crafted telnet commands, potentially gaining full administrative control over network infrastructure without requiring prior authentication.

Affected Products

• Extreme Networks EXOS versions before 32.5.1.5
• Extreme Networks EXOS versions before 22.7
• Extreme Networks EXOS versions before 31.7.2

Discovery Timeline

• 2023-10-16 - CVE-2023-43119 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2023-43119

Vulnerability Analysis

This vulnerability stems from improper access control (CWE-863) and incorrect authorization (CWE-284) within the Extreme Networks EXOS platform. The flaw exists in how the switch engine handles telnet commands that interact with an internal Redis server instance.

The attack requires network access to the affected device, but does not require authentication or user interaction to exploit. Successful exploitation results in complete compromise of confidentiality, integrity, and availability of the affected system. An attacker could potentially modify switch configurations, intercept network traffic, disrupt network operations, or use the compromised switch as a pivot point for further attacks within the network infrastructure.

Root Cause

The vulnerability exists due to insufficient access control validation when processing telnet commands that interact with the Redis server component. The EXOS platform fails to properly restrict which commands can be executed and by whom, allowing unauthenticated users to bypass authorization mechanisms and execute privileged operations.

This represents a fundamental flaw in the authorization layer where the Redis server interface is exposed without adequate protection, enabling attackers to leverage this internal service for privilege escalation.

Attack Vector

The attack is network-based and can be executed remotely against any exposed EXOS switch. The attacker crafts malicious telnet commands targeting the Redis server interface to bypass normal authentication and authorization controls. Due to the low complexity of the attack and the lack of required privileges or user interaction, this vulnerability is highly exploitable in environments where EXOS switches are accessible over the network.

The attacker would typically connect to the management interface of the switch via telnet and send specially crafted commands that exploit the improper access controls in the Redis server communication pathway, ultimately achieving elevated privileges on the device.

Detection Methods for CVE-2023-43119

Indicators of Compromise

• Unusual telnet connection attempts to EXOS switches, particularly from unauthorized sources
• Unexpected Redis-related commands or traffic patterns in switch logs
• Unauthorized configuration changes or privilege escalation events on EXOS devices
• Anomalous administrative sessions appearing without corresponding legitimate authentication events

Detection Strategies

• Monitor and alert on telnet connections to network infrastructure devices from non-administrative sources
• Implement network traffic analysis to detect unusual command patterns targeting switch management interfaces
• Review EXOS switch logs for unauthorized access attempts and privilege escalation indicators
• Deploy network segmentation monitoring to detect lateral movement from compromised switches

Monitoring Recommendations

• Enable comprehensive logging on all EXOS switches and forward logs to a centralized SIEM
• Configure alerts for any telnet connections from unexpected IP ranges or during unusual hours
• Monitor for Redis-specific commands or connection patterns that deviate from normal operational baselines
• Implement baseline profiling for switch management traffic to identify anomalous activity

How to Mitigate CVE-2023-43119

Immediate Actions Required

• Upgrade all affected Extreme Networks EXOS switches to version 32.5.1.5, 22.7, or 31.7.2 or later immediately
• Restrict network access to switch management interfaces using ACLs and network segmentation
• Disable telnet access where possible and use SSH for remote management
• Audit all EXOS switches to identify potentially compromised devices

Patch Information

Extreme Networks has released fixed versions addressing this vulnerability. Organizations should upgrade to one of the following patched versions:

• EXOS 32.5.1.5 or later
• EXOS 22.7 or later (for legacy deployments)
• EXOS 31.7.2 or later

Detailed patch information and upgrade guidance is available through the Extreme Networks Security Advisory.

Workarounds

• Implement strict network access controls limiting management interface exposure to authorized administrator IPs only
• Disable telnet access on all EXOS switches and migrate to SSH-based management
• Deploy firewall rules blocking unauthorized access to switch management ports
• Segment network management traffic onto dedicated VLANs with strict access controls
• Monitor Redis server ports and block external access to internal services on switches

# Example ACL configuration to restrict management access
# Apply to management interface to limit access to authorized networks
configure access-list management_acl permit ip 10.0.100.0/24
configure access-list management_acl deny ip any