Summary:
- Horizon3 analysis reveals a hard-coded JSON Web Token as the root cause of the exploit.
- CVE-2025-20188 affects the Out-of-Band Access Point Download feature in Cisco IOS XE Software for WLCs.
- Diffing techniques were used to locate the hard-coded JWT in Lua scripts, leading to vulnerability discovery.
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Article:
A recent analysis by Horizon3 has shed light on a critical vulnerability in Cisco IOS XE Software for WLCs. The exploit, tracked as CVE-2025-20188, stems from a hard-coded JSON Web Token (JWT) used for authentication in the Out-of-Band Access Point (AP) Download feature. This flaw allows attackers to bypass credential authentication and gain unauthorized access to the system.
To uncover the source of the vulnerability, Horizon3 researchers employed diffing techniques to compare file system contents from ISO images. By examining Lua scripts, they identified significant changes that pointed to the presence of hard-coded JWT tokens and keys. This discovery highlighted the crucial role played by these scripts in the exploit, prompting further investigation.
By conducting a comprehensive search across the source code, the researchers were able to pinpoint the exact locations where the Lua scripts were invoked. This meticulous process not only helped in understanding the impact of the vulnerability but also provided valuable insights for remediation efforts. Horizon3 emphasized the importance of eliminating hard-coded secrets, implementing robust file upload validation, and maintaining vigilant patch management practices to mitigate similar risks in the future.
In conclusion, the Horizon3 analysis serves as a stark reminder of the importance of proactive security measures in safeguarding critical systems. By staying vigilant and adopting best practices in authentication workflows and vulnerability management, organizations can effectively mitigate the risks posed by hard-coded secrets and prevent potential exploits.
