Cisco IOS XE NETCONF Flaw Enables Remote Root Access

Cisco has disclosed three critical privilege escalation vulnerabilities in its IOS XE Software, allowing authenticated attackers to gain root access on affected devices.

Tracked as CVE-2025-20197, CVE-2025-20198, and CVE-2025-20199, these flaws carry a CVSS score of 6.7 and affect the command-line interface (CLI) component across multiple IOS XE versions.

Technical Breakdown

The vulnerabilities stem from insufficient input validation when processing specific configuration commands (CWE-20).

Attackers with privilege level 15 access – typically administrative credentials – can craft malicious CLI inputs to bypass security checks and escalate privileges to the underlying Linux-based operating system’s root account.

Cisco’s Security Impact Rating (SIR) was elevated to High due to the potential for persistent, undetectable system compromises.

Attack Vectors

• Local Exploitation: Requires existing administrative access to the device CLI
• Command Injection: Malicious payloads embedded in configuration commands like: bashconfigure terminal !vulnerable_command malicious_payload
• Persistence Mechanisms: Root access enables creation of hidden backdoors and configuration changes

Affected Systems

The vulnerabilities impact all devices running unpatched IOS XE Software, including:

• Catalyst 9000 Series Switches
• ASR 1000 Series Routers
• ISR 4000 Series Routers
• Enterprise Network Function Virtualization Infrastructure

Cisco’s May 2025 Security Advisory Bundle confirms these flaws don’t affect IOS XR, NX-OS, or Meraki platforms.

Mitigation Strategies

Cisco recommends immediate upgrades to fixed software versions available through standard support channels. The company’s Software Checker tool helps identify vulnerable systems using IOS XE releases like:

• 17.9.3a (EOL)
• 16.12.9s
• 15.8(3)m

Security Implications
Successful exploitation enables:

1. Full device compromise through root access
2. Bypass of network segmentation controls
3. Tampering with firmware and boot processes
4. Credential harvesting from privileged memory spaces

The NETCONF-related vulnerability (CVE-2025-20200) adds remote attack potential via crafted API requests, though this requires valid administrator credentials.

Enterprise Response

Network administrators should:

1. Audit user accounts with privilege level 15 access
2. Monitor for unusual CLI activity patterns
3. Implement strict change control procedures
4. Schedule maintenance windows for emergency patching

Cisco’s TAC team reports no active exploits in the wild, but emphasizes the critical nature of these vulnerabilities given attackers’ ability to manipulate device configurations at the OS level.

The company continues security hardening efforts through its Advanced Security Initiatives Group (ASIG), which discovered these flaws during internal testing.

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