CVE-1999-0248
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 · uneditedA race condition in the authentication agent mechanism of sshd 1.2.17 allows an attacker to steal another user's credentials.
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 confidenceA race condition in the authentication agent mechanism of sshd version 1.2.17 allows a remote or local attacker to intercept and steal another user's authentication credentials during the authentication process, potentially gaining unauthorized access to the compromised user's account or resources.
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= 1.2.27CVSS 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
- Low
- Authentication
- None
- Confidentiality
- Complete
- Integrity
- Complete
- Availability
- Complete
AV:N/AC:L/Au:N/C:C/I:C/A:C
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 if sshd is installedRun 'which sshd' or check common locations like /usr/sbin/sshd, /usr/local/sbin/sshd, or look for sshd processes with 'ps aux | grep sshd'Affected if sshd is not found or not running, the system is not affected by this specific vulnerability
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Determine the sshd versionRun 'sshd -v' or 'sshd -V' to display the version. If those flags are not available, check the binary with 'sshd --help' or use 'strings /path/to/sshd | grep -i version'Affected if The version is 1.2.17 exactly, indicating the affected version
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Check if using SSH protocol version 1Review sshd configuration files (typically /etc/ssh/sshd_config) for 'Protocol' setting, or connect with verbose mode 'ssh -v' to see which protocol is negotiatedAffected if Protocol 1 is enabled or being used, as this vulnerability affects the SSH1 authentication agent mechanism in version 1.2.17
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Verify the authentication agent is in useCheck for running ssh-agent processes with 'ps aux | grep ssh-agent' and examine SSH_AUTH_SOCK environment variable with 'echo $SSH_AUTH_SOCK'Affected if SSH authentication agent is active and being used, which is required for the race condition to be exploitable
The system is affected if sshd version 1.2.17 is running with SSH protocol 1 and the authentication agent is in use, allowing an attacker to intercept credentials during the authentication process.
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.
dbcve · scopedUpgrade from sshd 1.2.17 to a patched version (SSH 1.2.31 or later, or preferably migrate to SSH2/OpenSSH). If immediate upgrade is not feasible, disable sshd and use alternative secure authentication methods until the upgrade can be completed.
OpenSSH 9.x or later (modern SSH2-only implementation)
- 1. Identify all systems still running SSH version 1.x (ssh 1.2.27)
- 2. Disable SSH protocol version 1 on any systems running modern OpenSSH that may still have SSH1 enabled (set 'Protocol 2' in /etc/ssh/sshd_config)
- 3. Upgrade to a modern SSH implementation such as OpenSSH 9.x or later, or a current commercial SSH product
- 4. For legacy systems that cannot run modern SSH, consider network-level restrictions or replacing the system entirely
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation8.0 h
- Implementation16.0 h
- Testing8.0 h
- Review / QA4.0 h
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Free · runs locallyCheck whether your project pulls in CVE-1999-0248 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
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-1999-0248 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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- Version or environment caveats, and links to real fixes
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