Full Report
I was recently playing with a Wingate Proxy server, came across some arbitrary interestingness. So, WinGate proxy includes a remote management agent which is accessed via a client utility called GateKeeper. This allows one to configure the WinGate server across the network. However, its not enabled to listen on the network by default, and only listens on 127.0.0.1:808. From my perusal of the documentation, the remote administrative facility should only be available to enterprise and professional license holders, and those firms using standard edition licenses will have to configure their proxy software locally.
Analysis Summary
# Vulnerability: WinGate Proxy Unauthorized Remote Administration Access via Tunneling
## CVE Details
- CVE ID: Not explicitly assigned in the source material. This appears to be an un-numbered or locally disclosed vulnerability at the time of publication (2009).
- CVSS Score: N/A (Score not provided)
- CWE: CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor) or CWE-749 (Missing Authentication for Critical Function).
## Affected Systems
- Products: WinGate Proxy Server
- Versions: Specific vulnerable versions are not listed, but the vulnerability concerns the default configuration of the remote management agent (GateKeeper agent). It likely affects versions available around 2009.
- Configurations: Any installation where the WinGate Proxy Server allows unauthenticated tunneling (via `CONNECT` method) to the internal loopback management interface (`127.0.0.1:808`), regardless of license type (Standard, Professional, Enterprise).
## Vulnerability Description
The WinGate Proxy server supports the HTTP `CONNECT` method, typically used for establishing SSL tunnels. However, the proxy lacks proper access control checks to prevent internal network requests made via this tunneling mechanism from being forwarded to the local loopback address (`127.0.0.1:808`) where the remote administration agent (GateKeeper) listens. Since the GateKeeper service binding might only be restricted to `127.0.0.1` by default, an attacker who can initiate a `CONNECT` request through the proxy can effectively tunnel arbitrary traffic, bypassing any assumptions that the administration service is only locally accessible, thus gaining unauthorized administrative access.
## Exploitation
- Status: PoC created and demonstrated via the tool `MonSoen.py`.
- Complexity: Low (Requires an attacker to be able to send HTTP requests to the proxy, leveraging the default `CONNECT` method functionality).
- Attack Vector: Network (Remote user interacting with the proxy service).
## Impact
- Confidentiality: High (Exposure of administrative configuration data).
- Integrity: High (Ability to modify proxy rules, forward traffic, change settings).
- Availability: Medium (Potential for denial of service or configuration disruption).
## Remediation
### Patches
- Patches are not specified in the source material. Users should consult WinGate vendor advisories for the relevant version updates that address this specific blind tunneling/access control bypass.
### Workarounds
1. **Disable the Remote Management Agent:** If remote management is not required, the GateKeeper agent should be disabled or configured not to start.
2. **Restrict Listener Binding:** If possible via configuration, verify that the GateKeeper agent is explicitly bound only to the desired local addresses, or preferably restricted to specific internal/trusted networks only, if binding to the loopback is necessary.
3. **Enforce Proxy Access Controls:** Ensure that the WinGate proxy service itself applies strong access control lists (ACLs) or authentication checks before processing requests, especially those attempting to utilize the `CONNECT` method for internal redirects or tunneling.
## Detection
- Indicators of Compromise: Significant outbound or internal traffic directed specifically at port 808/TCP on loopback addresses originating from the proxy layer. Unusual configuration changes originating from the proxy server itself immediately following connection attempts.
- Detection methods and tools: Network or host-based intrusion detection systems (NIDS/HIDS) monitoring for unusual HTTP `CONNECT` requests that resolve internally to loopback destinations. The use of the custom tool `MonSoen.py` could be signatured if deployed in the environment.
## References
- Vendor Advisories: None provided in the source.
- Relevant links - defanged:
- Research Page: http://www.sensepost.com/research_misc.html
- Tool reference: http://packetstormsecurity.org/UNIX/scanners/pbs.c
- Python module dependency: http://pypi.python.org/pypi/netaddr