A flaw was found in the util-linux chfn and chsh utilities when compiled with Readline support. The Readline library uses an INPUTRC environment variable to get a path to the library config file. When the library cannot parse the specified file, it prints an error message containing data from the file. This flaw allows an unprivileged user to read root-owned files, potentially leading to privilege escalation. This flaw affects util-linux versions prior to 2.37.4.
The product generates an error message that includes sensitive information about its environment, users, or associated data.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Util-linux | Kernel | * | 2.37.4 (excluding) |
| Util-linux | Ubuntu | trusty | * |
| Util-linux | Ubuntu | xenial | * |
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.