CVE-2018-25111: 
Python vulnerability analysis and mitigation

django-helpdesk before version 1.0.0 contains a sensitive data exposure vulnerability due to insecure file permissions settings in models.py. The vulnerability is tracked as CVE-2018-25111 and stems from the use of os.umask(0), which allows files and directories to be created with permission 777 (GitHub Issue).

The vulnerability exists in models.py where the statement os.umask(0) on lines 1140 and 1162 allows files and directories to be created with permission 777. This leads to CWE-732 (Incorrect Permission Assignment for Critical Resource). After the execution of this code, any files or directories are created with the same mask, resulting in permissions like -rw-rw-rw- or drwxrwxrwx. However, the uploaded files themselves are created with permission 644 due to Django's FILEUPLOADPERMISSIONS setting (GitHub PR).

The vulnerability allows files and directories to be created with overly permissive access rights (777), which could potentially allow unauthorized access to sensitive data stored in the attachment directories. This insecure permission setting could lead to information disclosure or unauthorized modification of stored files (GitHub PR).

The vulnerability has been fixed in version 1.0.0 by removing the os.umask(0) statements and implementing configurable directory permissions through a new setting HELPDESKATTACHMENTDIR_PERMS. The fix sets a default permission of 755 for attachment directories while maintaining the ability to configure stricter permissions if needed (GitHub Release).