CVE-2023-48643
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 · uneditedShrubbery tac_plus 2.x, 3.x. and 4.x through F4.0.4.28 allows unauthenticated Remote Command Execution. The product allows users to configure authorization checks as shell commands through the tac_plus.cfg configuration file. These are executed when a client sends an authorization request with a username that has pre-authorization directives configured. However, it is possible to inject additional commands into these checks because strings from TACACS+ packets are used as command-line arguments. If the installation lacks a a pre-shared secret (there is no pre-shared secret by default), then the injection can be triggered without authentication. (The attacker needs to know a username configured to use a pre-authorization command.) NOTE: this is related to CVE-2023-45239 but the issue is in the original Shrubbery product, not Meta's fork.
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 · high confidenceThe Shrubbery tac_plus TACACS+ server allows configuration of authorization checks as shell commands in tac_plus.cfg. These commands execute when a client sends an authorization request with a username that has pre-authorization directives. The vulnerability stems from using strings from TACACS+ packets directly as command-line arguments without sanitization, enabling command injection. When no pre-shared secret is configured (the default), the injection is exploitable without any authentication, requiring only knowledge of a username configured with pre-authorization commands.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS 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
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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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Locate the tac_plus configuration fileSearch for tac_plus.cfg in typical locations such as /etc/tac_plus.cfg, /usr/local/etc/tac_plus.cfg, or the current working directoryAffected if The file exists and contains authorization directives with shell command executions (e.g., cmd = execute or similar patterns)
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Identify authorization commands in the configOpen the tac_plus.cfg file and search for lines containing shell command execution patterns, such as 'cmd = "/bin/sh"', 'cmd = "/usr/bin/"', or any 'execute' directive that runs an external commandAffected if The configuration contains any shell command execution tied to authorization directives (this is the vulnerable feature)
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Check if pre-shared secret is configuredIn tac_plus.cfg, look for a 'key' or 'secret' directive under the server configuration, or check if the configuration lacks any key statement entirelyAffected if No pre-shared secret is configured (key directive is missing or commented out), which allows unauthenticated exploitation
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Identify usernames with pre-authorization directivesSearch the config for user blocks that contain 'preauthorization' or 'cmd' directives that trigger the shell command executionAffected if Any user account is configured with pre-authorization commands that execute shell commands
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Verify tac_plus is runningCheck running processes with 'ps aux | grep tac_plus' or check for the service listening on port 49 (TACACS+ default port)Affected if The vulnerable tac_plus service is active and processing requests
You are affected if tac_plus is running with a configuration that uses shell commands in authorization directives and either lacks a pre-shared secret or exposes users with pre-authorization commands accessible to attackers.
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 dataImmediately configure a strong pre-shared secret in tac_plus to require authentication for all requests. Review and sanitize or remove shell command executions in authorization directives, and monitor for unauthorized access attempts.
- Consultation3.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2023-48643 — 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-2023-48643 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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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
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