CVE-2020-3442 DuoConnect SSH Connection Vulnerability
An attacker on the same network can sniff insecure HTTP traffic to steal authentication tokens, potentially gaining network-level access to protected SSH servers.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2020-3442?
CVE-2020-3442 is a medium-severity vulnerability in Cisco DUO Connect, published on 20 Jul 2020. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
The DuoConnect client enables users to establish SSH connections to hosts protected by a DNG instance. When a user initiates an SSH connection to a DNG-protected host for the first time using DuoConnect, the user’s browser is opened to a login screen in order to complete authentication determined by the contents of the '-relay' argument. If the ‘-relay’ is set to a URL beginning with "http://", then the browser will initially attempt to load the URL over an insecure HTTP connection, before being immediately redirected to HTTPS (in addition to standard redirect mechanisms, the DNG uses HTTP Strict Transport Security headers to enforce this). After successfully authenticating to a DNG, DuoConnect stores an authentication token in a local system cache, so users do not have to complete this browser-based authentication workflow for every subsequent SSH connection. These tokens are valid for a configurable period of time, which defaults to 8 hours. If a user running DuoConnect already has a valid token, then instead of opening a web browser, DuoConnect directly contacts the DNG, again using the configured '-relay' value, and sends this token, as well as the intended SSH server hostname and port numbers. If the '-relay' argument begins with "http://", then this request will be sent over an insecure connection, and could be exposed to an attacker who is sniffing the traffic on the same network. The DNG authentication tokens that may be exposed during SSH relay may be used to gain network-level access to the servers and ports protected by that given relay host. The DNG provides network-level access only to the protected SSH servers. It does not interact with the independent SSH authentication and encryption. An attacker cannot use a stolen token on its own to authenticate against a DNG-protected SSH server.
Weakness: CWE-319
Which versions are affected by CVE-2020-3442?
It affects 1 product.
Products include Duo Duoconnect.
How do I fix CVE-2020-3442?
No fix has been published for CVE-2020-3442 yet. Limit exposure of the affected software until one is available.
Is CVE-2020-3442 being exploited?
There is no known exploitation of CVE-2020-3442 in the wild and no public exploit code.
Sources
Also known as GHSA-83vc-pmxf-g524.