Improper sanitisation in main/inc/lib/fileUpload.lib.php in Chamilo LMS <= v1.11.20 on Windows and Apache installations allows unauthenticated attackers to bypass file upload security protections and obtain remote code execution via uploading of .htaccess file. This vulnerability may be exploited by privileged attackers or chained with unauthenticated arbitrary file write vulnerabilities, such as CVE-2023-3533, to achieve remote code execution.
Weakness
The product does not properly account for differences in case sensitivity when accessing or determining the properties of a resource, leading to inconsistent results.
Affected Software
| Name |
Vendor |
Start Version |
End Version |
| Chamilo |
Chamilo |
* |
1.11.20 (including) |
Extended Description
Improperly handled case sensitive data can lead to several possible consequences, including:
Potential Mitigations
- Assume all input is malicious. Use an “accept known good” input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
- When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, “boat” may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as “red” or “blue.”
- Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code’s environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
References