Overview
A significant security flaw has been uncovered within the LB-LINK BL-AC3600 1.0.22 router software. The vulnerability, identified as CVE-2025-7564, has been classified as critical, affecting unknown functionality of the /etc/shadow file within the software. This vulnerability matters because it allows for manipulation of the root:blinkadmin input, leading to the exposure of hard-coded credentials. This could potentially provide unauthorized users with access to the system, resulting in a severe security breach. The exploit has been publicly disclosed, and despite the vendor being notified, no response or solution has been provided.
Vulnerability Summary
CVE ID: CVE-2025-7564
Severity: Critical (7.8)
Attack Vector: Local
Privileges Required: None
User Interaction: Required
Impact: System compromise, data leakage
Affected Products
Escape the Surveillance Era
Most apps won’t tell you the truth.
They’re part of the problem.
Phone numbers. Emails. Profiles. Logs.
It’s all fuel for surveillance.
Ameeba Chat gives you a way out.
- • No phone number
- • No email
- • No personal info
- • Anonymous aliases
- • End-to-end encrypted
Chat without a trace.
Product | Affected Versions
LB-LINK BL-AC3600 | 1.0.22
How the Exploit Works
The vulnerability exists due to an insecure mechanism of handling input within the /etc/shadow file of LB-LINK BL-AC3600 1.0.22 software. The flaw allows a local user to manipulate the root:blinkadmin input, revealing hard-coded credentials. These credentials provide unauthorized access to the system and can lead to data leakage and potential system compromise.
Conceptual Example Code
In this scenario, a local user could potentially exploit this vulnerability through a command-line interface. The following is a conceptual representation of how this could be executed:
$ echo 'root:blinkadmin' >> /etc/shadow
$ su - root
Password: [hard-coded password]
#In this example, the attacker appends ‘root:blinkadmin’ to the /etc/shadow file and then attempts to switch to the root user using the disclosed hard-coded password. If successful, the attacker gains root access to the system, leading to a potential system compromise.
Mitigation Guidance
Due to the lack of a vendor-supplied patch, users are advised to implement a Web Application Firewall (WAF) or Intrusion Detection System (IDS) as temporary mitigation. These measures can help detect and block attempts to exploit this vulnerability. Users should also stay vigilant for any updates or patches released by the vendor to fix this critical flaw in the LB-LINK BL-AC3600 1.0.22 software.
