CVE-2025-9577 Overview
CVE-2025-9577 affects the TOTOLINK X2000R router firmware up to version 2.0.0. The flaw resides in an unknown function within the /etc/shadow.sample file of the Administrative Interface component. The vulnerability stems from the use of default credentials [CWE-1392], allowing local attackers with low privileges to leverage pre-shipped account values that were never rotated at deployment.
Public disclosure includes reproduction steps, and the exploit code is available. However, exploitation requires local access and involves high attack complexity, limiting practical abuse in most deployments.
Critical Impact
A local attacker holding low-privilege access can leverage default credentials embedded in /etc/shadow.sample to gain unauthorized access to router administrative functionality.
Affected Products
- TOTOLINK X2000R firmware version 2.0.0-b20230727.1043.web
- TOTOLINK X2000R hardware device
- TOTOLINK X2000R firmware versions up to and including 2.0.0
Discovery Timeline
- 2025-08-28 - CVE-2025-9577 published to NVD
- 2026-07-25 - Last updated in NVD database
Technical Details for CVE-2025-9577
Vulnerability Analysis
The TOTOLINK X2000R router ships with a /etc/shadow.sample file that contains default credential material [CWE-1392]. The file is part of the Administrative Interface component and stores hashed password entries that are static across devices in the affected firmware line.
An attacker with local access and low-level privileges can read or reference these default credentials to authenticate against administrative functionality. Because the shadow-format sample is reused across shipped units, credentials extracted from one device remain valid on other devices running the same firmware image.
The weakness is classified under CWE-1392: Use of Default Credentials. Exploitation is documented in a public GitHub PoC Repository.
Root Cause
The root cause is the inclusion of static, factory-provisioned credential material inside the firmware image without enforcing a mandatory credential change during first-time device setup. The /etc/shadow.sample file persists across devices, allowing credential reuse.
Attack Vector
The attack vector is local. An adversary needs prior local access to the device or its administrative interface, along with a low-privilege foothold. Attack complexity is high, and the reproduction steps demonstrate a non-trivial exploitation path.
No verified exploit code is included here; refer to the linked repository for technical reproduction details.
Detection Methods for CVE-2025-9577
Indicators of Compromise
- Presence of unmodified /etc/shadow.sample contents on deployed TOTOLINK X2000R devices
- Administrative interface logins originating from local network segments that should not have privileged access
- Configuration changes on the router that do not correlate with authorized administrator activity
Detection Strategies
- Audit TOTOLINK X2000R firmware versions across the environment and flag devices running 2.0.0 or earlier
- Compare /etc/shadow entries against the shipped /etc/shadow.sample file to identify credentials that were never rotated
- Monitor router administrative interface authentication logs for unexpected successful logins
Monitoring Recommendations
- Baseline management-plane access to network devices and alert on deviations from that baseline
- Forward router syslog data to a centralized logging system for correlation with other network telemetry
- Track configuration diffs on TOTOLINK devices and alert on out-of-band changes
How to Mitigate CVE-2025-9577
Immediate Actions Required
- Rotate all administrative credentials on affected TOTOLINK X2000R units and confirm the default values from /etc/shadow.sample are no longer active
- Restrict access to the router administrative interface to trusted management networks only
- Inventory all TOTOLINK X2000R deployments and identify units running firmware 2.0.0 or earlier
Patch Information
No vendor advisory or patched firmware release has been published in the referenced sources at the time of NVD publication. Consult the TOTOLINK Official Website for firmware updates and vendor guidance specific to the X2000R product line.
Workarounds
- Force a mandatory password change on all administrative accounts and remove or overwrite the /etc/shadow.sample reference where feasible
- Segment the router management interface onto a dedicated VLAN with strict access control lists
- Disable remote administrative access and require console or wired LAN access for configuration changes
- Consider replacing affected units with hardware that supports secure default-credential handling if a vendor patch is not released
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
