CVE-2024-20439
A vulnerability in Cisco Smart Licensing Utility (CSLU) could allow an unauthenticated, remote attacker to log into an affected system by using a static…
- Severity
- 9.8 / 10
- Critical · CVSS 3.1
- Exploit chance (EPSS)
- 97.09%
- Chance of exploitation in the next 30 days. Higher than 99.89% of scored vulnerabilities.
- Known exploited
- Yes
- In CISA's catalog since Mar 31, 2025
- Fix
- None yet
- No fixed version published
Description
A vulnerability in Cisco Smart Licensing Utility (CSLU) could allow an unauthenticated, remote attacker to log into an affected system by using a static administrative credential. This vulnerability is due to an undocumented static user credential for an administrative account. An attacker could exploit this vulnerability by using the static credentials to login to the affected system. A successful exploit could allow the attacker to login to the affected system with administrative rights over the CSLU application API.
How to fix
No fixed version has been published yet. Until one is, remove or replace the package, or turn off or isolate the affected feature. This page updates when a fix ships.
Severity breakdown
CVSS 3.1 9.8
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Weakness
CWE-912: Hidden Functionality
The product contains functionality that is not documented, not part of the specification, and not accessible through an interface or command sequence that is obvious to the product's users or administrators.
How to prevent it
- Installation: Always verify the integrity of the product that is being installed.
CWE-798: Use of Hard-coded Credentials
The product contains hard-coded credentials, such as a password or cryptographic key.
How to prevent it
- Architecture and Design: For outbound authentication: store passwords, keys, and other credentials outside of the code in a strongly-protected, encrypted configuration file or database that is protected from access by all outsiders, including other local users on the same system. Properly protect the key (CWE-320). If you cannot use encryption to protect the file, then make sure that the permissions are as restrictive as possible [REF-7]. In Windows environments, the Encrypted File System (EFS) may provide some protection.
- Architecture and Design: For inbound authentication: Rather than hard-code a default username and password, key, or other authentication credentials for first time logins, utilize a "first login" mode that requires the user to enter a unique strong password or key.
- Architecture and Design: If the product must contain hard-coded credentials or they cannot be removed, perform access control checks and limit which entities can access the feature that requires the hard-coded credentials. For example, a feature might only be enabled through the system console instead of through a network connection.
- Architecture and Design: For inbound authentication using passwords: apply strong one-way hashes to passwords and store those hashes in a configuration file or database with appropriate access control. That way, theft of the file/database still requires the attacker to try to crack the password. When handling an incoming password during authentication, take the hash of the password and compare it to the saved hash. Use randomly assigned salts for each separate hash that is generated. This increases the amount of computation that an attacker needs to conduct a brute-force attack, possibly limiting the effectiveness of the rainbow table method.
- Architecture and Design: For front-end to back-end connections: Three solutions are possible, although none are complete. The first suggestion involves the use of generated passwords or keys that are changed automatically and must be entered at given time intervals by a system administrator. These passwords will be held in memory and only be valid for the time intervals. Next, the passwords or keys should be limited at the back end to only performing actions valid for the front end, as opposed to having full access. Finally, the messages sent should be tagged and checksummed with time sensitive values so as to prevent replay-style attacks.
References
Advisories
Other links
Timeline
- Published
- Added to CISA's Known Exploited Vulnerabilities catalog
- Remediation due for U.S. federal agencies
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-9wfr-w7mm-pc7f Electron: Renderer command-line switch injection via undocumented commandLineSwitches webPreference | High | Same weakness, CWE-912 |
| CVE-2025-47729 The TeleMessage archiving backend through 2025-05-05 holds cleartext copies of messages from TM SGNL (aka Archive Signal) app users, which is different… | Medium Known exploited | Same weakness, CWE-912 |
| GHSA-j9cw-5cpj-9qj5 Moodle has a Hidden Functionality vulnerability | Medium | Same weakness, CWE-912 |
| CVE-2021-25371 A vulnerability in DSP driver prior to SMR Mar-2021 Release 1 allows attackers load arbitrary ELF libraries inside DSP. | Medium Known exploited | Same weakness, CWE-912 |
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