It was found that dropbear before version 2013.59 with GSSAPI leaks whether given username is valid or invalid. When an invalid username is given, the GSSAPI authentication failure was incorrectly counted towards the maximum allowed number of password attempts.
The product generates an error message that includes sensitive information about its environment, users, or associated data.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Dropbear_ssh | Dropbear_ssh_project | * | 2013.59 (excluding) |
| Dropbear | Ubuntu | upstream | * |
The sensitive information may be valuable information on its own (such as a password), or it may be useful for launching other, more serious attacks. The error message may be created in different ways:
An attacker may use the contents of error messages to help launch another, more focused attack. For example, an attempt to exploit a path traversal weakness (CWE-22) might yield the full pathname of the installed application. In turn, this could be used to select the proper number of “..” sequences to navigate to the targeted file. An attack using SQL injection (CWE-89) might not initially succeed, but an error message could reveal the malformed query, which would expose query logic and possibly even passwords or other sensitive information used within the query.