CLI Baseline B13 - TOCTOU / symlink race

cli-baseline-b13-toctou-symlink-race is a high severity check in the cli-baseline category, written in shell. Its source is templates/cli-baseline/cli-baseline-b13-toctou-symlink-race.sh in cert-x-gen-templates.

What it checks

Races a symlink swap against the target’s check-then-use window. If the canary behind the symlink is written or read, the check was against a path and the use resolved it again.

Header

Field	Value
Id	cli-baseline-b13-toctou-symlink-race
Severity	high
Language	shell
Category	cli-baseline
Author	CERT-X-GEN / CLI Security Baseline
Template version	not recorded
Confidence	not recorded
CVSS	not recorded
Weakness	CWE-367
Tags	cli, baseline, toctou, race, symlink, cwe-367
Target kind	cli
Oracle	property

Conventions of the repository, not fields the engine reads

@target_kinds and @oracles are documented in the templates repository’s contribution guide, and cxg’s annotation parser does not carry them into a template’s metadata. Nothing at scan time selects on them. The annotation header schema is every field the parser does read.

The file declares @allow_nonzero_exit as well. Those are not tabled above; read the source for what they carry.

Run it

To see what the copy on your machine says about itself, and to confirm it is installed at all:

cxg template info cli-baseline-b13-toctou-symlink-race

The id it prints is the one to pass anywhere a template is selected. See cxg template for the rest of the subcommand, Scan a target for running a scan, and A match is not a finding for how to read what comes back.

Related

• Template catalog is the whole corpus.
• cli-baseline is the rest of this category.
• Templates by weakness class groups checks by the defect they look for.
• Contribute a template is the route from a check you needed and could not find to a merged one.