CVE-2000-0217
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedThe default configuration of SSH allows X forwarding, which could allow a remote attacker to control a client's X sessions via a malicious xauth program.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceThe default SSH configuration enables X11 forwarding, which allows the SSH server to tunnel X11 traffic between the client and server. A remote attacker who controls the server or performs a man-in-the-middle attack could inject a malicious xauth program or command, potentially allowing them to intercept, manipulate, or take control of the client's X sessions.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data= 1.2= 1.2.0= 1.2.1= 1.2.2= 1.2.3= 1.2.4= 1.2.5= 1.2.6= 1.2.7= 1.2.8= 1.2.9= 1.2.10= 1.2.11= 2.0= 2.0.1= 2.0.2= 2.0.3= 2.0.4= 2.0.5= 2.0.6= 2.0.7= 2.0.8= 2.0.9= 2.0.10= 2.0.11CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- High
- Authentication
- None
- Confidentiality
- Partial
- Integrity
- Partial
- Availability
- Partial
AV:N/AC:H/Au:N/C:P/I:P/A:P
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify the installed SSH server versionRun `sshd -v 2>&1` or `sshd -V 2>&1` to display the version. On some systems check `/usr/sbin/sshd -v` or look for the sshd version in the package manager output with `dpkg -l openssh-server` or `rpm -q openssh-server`.Affected if The version matches any of: OpenSSH 1.2, SSH 1.2.0-1.2.11, or SSH2 2.0-2.0.11.
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Locate the SSH daemon configuration fileThe primary configuration file is typically located at `/etc/ssh/sshd_config` or `/etc/sshd_config`. Verify this file exists and is readable.Affected if The configuration file exists at the standard path.
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Check if X11Forwarding is explicitly disabledSearch the sshd_config file for the X11Forwarding directive using `grep -i X11Forwarding /etc/ssh/sshd_config` or `cat /etc/ssh/sshd_config | grep X11Forwarding`.Affected if X11Forwarding is either not present in the config OR is set to 'yes' (the default when not specified in these older versions). If X11Forwarding is set to 'no', the system is not vulnerable via this configuration.
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Verify the effective X11 forwarding stateIf the SSH server is running, check the actual runtime configuration with `sshd -T 2>/dev/null | grep -i x11forwarding`. This shows the effective setting after applying defaults.Affected if The output shows 'x11forwarding yes' or the directive is absent, meaning X11 forwarding is enabled by default.
If the SSH server version is one of the affected versions (OpenSSH 1.2, SSH 1.2.x, or SSH2 2.0.x through 2.0.11) AND X11Forwarding is not explicitly set to 'no' in the configuration, the system is vulnerable to X11 session hijacking via a malicious SSH server or MITM attack.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataDisable X11 forwarding in the SSH configuration (/etc/ssh/sshd_config) by setting 'X11Forwarding no' unless explicitly required, and restrict X11 display forwarding with 'X11DisplayOffset' and 'XAuthLocation' directives.
- Consultation1.0 h
- Implementation1.0 h
- Testing2.0 h
- Review / QA1.0 h
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2000-0217 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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