CVE-2023-24509: Arista EOS Privilege Escalation Vulnerability

CVE-2023-24509 Overview

CVE-2023-24509 is a privilege escalation vulnerability affecting Arista EOS on modular platforms equipped with redundant supervisor modules. When the redundancy protocol is configured with Route Processor Redundancy (RPR) or Stateful Switchover (SSO), an existing unprivileged user can login to the standby supervisor as a root user, effectively bypassing normal access controls and gaining complete administrative privileges over the network device.

This vulnerability is particularly concerning for enterprise network environments where Arista modular switches form the backbone of critical infrastructure. The ability to escalate from a low-privileged user to root access on redundant supervisor modules could allow attackers to compromise network configurations, intercept traffic, or establish persistent access within the network.

Critical Impact

An authenticated low-privileged user can escalate to root on standby supervisor modules, potentially compromising entire network infrastructure segments running Arista EOS with redundancy configurations.

Affected Products

• Arista EOS (multiple versions on modular platforms)
• Arista 7300X Series (7304X, 7304X3, 7308X, 7316X, 7324X, 7328X)
• Arista 7500R Series (7504R, 7504R3, 7508R, 7508R3, 7512R, 7512R3, 7516R)
• Arista 7800R3 Series (7804R3, 7808R3, 7812R3, 7816R3)
• Arista 755X and 758X Series
• Arista 704X3

Discovery Timeline

• April 13, 2023 - CVE-2023-24509 published to NVD
• November 21, 2024 - Last updated in NVD database

Technical Details for CVE-2023-24509

Vulnerability Analysis

This privilege escalation vulnerability (CWE-269: Improper Privilege Management) exists in the authentication and session handling mechanisms between primary and standby supervisor modules in Arista EOS. The flaw specifically manifests when modular platforms are configured with redundancy protocols—either RPR (Route Processor Redundancy) or SSO (Stateful Switchover)—which are commonly deployed configurations in enterprise and data center environments to ensure high availability.

The vulnerability allows an authenticated user with minimal privileges to bypass the normal access control mechanisms when connecting to the standby supervisor module. Instead of maintaining the user's original privilege level, the standby supervisor grants root access, providing complete administrative control over that module. This represents a significant security boundary violation where the redundancy infrastructure fails to properly replicate and enforce user privilege levels.

Root Cause

The root cause of CVE-2023-24509 lies in improper privilege management during user session synchronization between redundant supervisor modules. When a user authenticates to the primary supervisor, their session information and credentials are synchronized to the standby supervisor as part of the redundancy protocol. However, the privilege level validation is not properly enforced on the standby module, allowing the user to obtain root privileges when directly accessing the standby supervisor.

This architectural flaw in the redundancy synchronization mechanism means that privilege boundaries established on the primary supervisor are not consistently maintained across the redundant infrastructure, creating an exploitable privilege escalation path.

Attack Vector

The attack vector requires local access and valid user credentials on the Arista EOS system. An attacker must:

1. Have existing credentials for any unprivileged user account on the affected Arista EOS system
2. Target a modular platform with redundant supervisor modules configured with RPR or SSO
3. Directly access the standby supervisor module rather than the primary
4. Upon login to the standby supervisor, the attacker receives root-level access

This exploitation path requires the attacker to have some level of authenticated access to the system initially, making insider threats or compromised user accounts the primary concern. Once root access is obtained on the standby supervisor, the attacker could manipulate network configurations, access sensitive data, or potentially pivot to affect the primary supervisor during a failover event.

Detection Methods for CVE-2023-24509

Indicators of Compromise

• Unexpected login sessions to standby supervisor modules, especially from user accounts that normally only access the primary supervisor
• User accounts operating with elevated privileges on standby supervisors that don't match their configured privilege levels
• Configuration changes or command executions on standby modules that require root access from accounts that shouldn't have such permissions
• Audit log discrepancies between primary and standby supervisor access patterns

Detection Strategies

• Monitor authentication logs on both primary and standby supervisor modules for login anomalies
• Implement alerting for any direct access attempts to standby supervisor consoles
• Compare user privilege levels between primary and standby modules during periodic security audits
• Deploy SentinelOne Singularity for network device visibility and anomalous access pattern detection

Monitoring Recommendations

• Enable comprehensive logging of all supervisor module access, including SSH, console, and API connections
• Configure SIEM integration to correlate access events across redundant supervisor modules
• Establish baseline access patterns and alert on deviations, particularly for standby module direct access
• Monitor for privilege-related commands executed by users on standby supervisors

How to Mitigate CVE-2023-24509

Immediate Actions Required

• Review and audit all user accounts with access to affected Arista EOS modular platforms
• Restrict network access to standby supervisor management interfaces using ACLs or firewall rules
• Implement network segmentation to limit which systems can reach supervisor module management interfaces
• Enable enhanced logging and monitoring on all redundant supervisor modules

Patch Information

Arista has released security patches addressing this vulnerability. Affected organizations should consult the Arista Security Advisory #0082 for specific version information and upgrade guidance. It is recommended to upgrade to the latest patched version of Arista EOS that addresses CVE-2023-24509 as soon as possible.

Organizations should prioritize patching based on the criticality of affected devices and their exposure level within the network architecture.

Workarounds

• Restrict direct access to standby supervisor modules by implementing strict management ACLs that limit connectivity to authorized management stations only
• Disable direct console and SSH access to standby supervisors where operationally feasible
• Implement out-of-band management networks with enhanced access controls for supervisor module management
• Consider temporarily operating without redundancy protocols (RPR/SSO) on highly sensitive systems until patches can be applied, though this reduces availability guarantees

# Example ACL configuration to restrict standby supervisor access
# Consult Arista documentation for specific syntax and implementation
# Configure management ACL on standby supervisor
ip access-list standard MGMT-ACCESS
   permit host 10.0.0.10    ! Authorized management station
   permit host 10.0.0.11    ! Secondary management station
   deny any log

# Apply to management interface
interface Management1
   ip access-group MGMT-ACCESS in