Horizon Alert
Summary of the vulnerability and why it matters
This issue in ntfy could allow an attacker to trick the system into making requests to unintended locations, potentially accessing or manipulating internal resources. It's important to address because it can lead to sensitive data exposure or unauthorized actions.
- Can affect systems reachable from the internet.
- Allows attackers to control requests made by the server.
- Could lead to data leaks or unauthorized access.
Attack Path
How an attacker could exploit the issue
An attacker can exploit this vulnerability to perform Server-Side Request Forgery (SSRF) attacks. This allows them to trick the ntfy server into making requests to arbitrary internal or external network resources on their behalf. This could be used to access sensitive information or interact with other services within the network.
- No authentication required.
- Targets the notification service's request handling.
- Exploits an unanchored regular expression.
Live Threat
Current exploitation, exposure, and threat context
This Server-Side Request Forgery vulnerability in ntfy, which allows unanchored regular expressions, could be attractive to attackers as it offers the potential for remote code execution or information disclosure. While there are no immediate indicators of widespread exploitation, the vulnerability's critical severity and the nature of SSRF vulnerabilities mean that targeted attacks are plausible.
- No KEV listing observed.
- Public exploit information exists.
- Patch released recently.
Priority actions
Operational Fix
Recommended remediation, mitigation, and detection steps
Prioritize patching or upgrading ntfy instances to version 2.22.0 or later to address the Server-Side Request Forgery vulnerability. If immediate patching is not feasible, implement network egress filtering and strictly control outbound traffic from affected servers to mitigate the risk of exploitation.
- Upgrade ntfy to 2.22.0.
- Block unexpected outbound traffic.
- Monitor for suspicious network connections.
