CVE-2024-20398
📋 TL;DR
This vulnerability in Cisco IOS XR Software allows authenticated local attackers with low-privileged accounts to gain root-level file system access through crafted CLI commands. Attackers can read and write files on the underlying operating system, leading to privilege escalation. Only Cisco IOS XR devices with vulnerable versions are affected.
💻 Affected Systems
- Cisco IOS XR Software
📦 What is this software?
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
⚠️ Risk & Real-World Impact
Worst Case
Attacker gains full root access, installs persistent backdoors, exfiltrates sensitive configuration data, and compromises the entire network infrastructure.
Likely Case
Privilege escalation to root, unauthorized configuration changes, credential theft, and lateral movement within the network.
If Mitigated
Limited to authorized users with CLI access, but still enables privilege escalation within the device.
🎯 Exploit Status
Exploitation requires authenticated CLI access. The vulnerability is in specific CLI commands with insufficient argument validation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Multiple fixed releases available (see Cisco advisory for specific versions)
Vendor Advisory: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-priv-esc-CrG5vhCq
Restart Required: Yes
Instructions:
1. Review Cisco advisory for exact fixed versions. 2. Download appropriate software from Cisco. 3. Backup configuration. 4. Install update following Cisco IOS XR upgrade procedures. 5. Reboot device. 6. Verify successful upgrade.
🔧 Temporary Workarounds
Restrict CLI Access
cisco-ios-xrLimit CLI access to trusted administrators only using AAA and role-based access control
aaa authentication login default group tacacs+ local
aaa authorization exec default group tacacs+ local
aaa accounting exec default start-stop group tacacs+
Implement Command Authorization
cisco-ios-xrUse TACACS+ with command authorization to restrict specific CLI commands
aaa authorization commands 15 default group tacacs+ local
🧯 If You Can't Patch
- Implement strict access controls: Only allow CLI access to absolutely necessary trusted administrators
- Enable comprehensive logging and monitoring of all CLI sessions and command execution
🔍 How to Verify
Check if Vulnerable:
Check IOS XR version with 'show version' and compare against vulnerable versions in Cisco advisoryCheck Version:
show version | include Cisco IOS XR SoftwareVerify Fix Applied:
After patching, verify version is updated to fixed release with 'show version' command📡 Detection & Monitoring
Log Indicators:
- Unusual CLI command patterns
- Multiple failed privilege escalation attempts
- Unexpected file system access logs
Network Indicators:
- Unusual administrative access patterns to devices
SIEM Query:
source="ios-xr" AND (event_type="cli_command" AND command CONTAINS suspicious_pattern) OR (event_type="privilege_escalation")