FOSSBilling is a free, open-source billing and client management system. Prior to version 0.8.0, the Redirect module does not validate the URL scheme of administrator-configured destination URLs before storing or issuing redirects. This allows arbitrary external URLs to be configured as redirect targets, creating an open redirect vulnerability exploitable for phishing attacks. Users following a legitimate FOSSBilling URL can be silently redirected to an attacker-controlled external site. The redirect is issued as a 301 (Moved Permanently) response, which browsers cache persistently, amplifying the impact. Exploitation requires administrator privileges to create or modify redirect entries, limiting practical attack scenarios to multi-admin environments or compromised admin accounts. Version 0.8.0 fixes the issue. Some workarounds are available. Restrict admin access to the Redirect module to trusted administrators only and/or audit existing redirect entries in the database (the `extension_meta` table with `extension = 'mod_redirect'`) for any unexpected or external target URLs.
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
| Attack Vector | NETWORK |
|---|---|
| Attack Complexity | LOW |
| Attack Requirements | NONE |
| Privileges Required | HIGH |
| User Interaction | PASSIVE |
| Vulnerability Confidentiality | NONE |
| Vulnerability Integrity | NONE |
| Vulnerability Availability | NONE |
| Subsequent Confidentiality | NONE |
| Subsequent Integrity | LOW |
| Subsequent Availability | NONE |
Source: [email protected]
Type: Secondary
| Source | Type | Description |
|---|---|---|
| [email protected] | Primary |
en
CWE-601
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