ATK Rule Pre-check for Wazuh: find ignored rules before you restart

Paste or point it at your custom Wazuh rule and decoder files. It tells you what wazuh-analysisd will report when it loads them: rules it will ignore because a parent is missing or loads later, duplicate IDs, and the mistakes that stop the manager from starting. It does not run Wazuh, reads files only, and sends nothing anywhere.

Three ways to run the same core:

• In the browser: https://atkvn.com/wazuh-rule-precheck.html (nothing is uploaded; the check runs in the tab)

• Command line: node cli.js /var/ossec/etc/rules /var/ossec/etc/decoders

• MCP server for any MCP client: mcp-server.js

Node.js 18 or newer. No dependencies.

Command line

git clone https://github.com/xuxu298/wazuh-rule-precheck
cd wazuh-rule-precheck
node cli.js /var/ossec/etc/rules /var/ossec/etc/decoders     # text report
node cli.js --json local_rules.xml                           # JSON
node cli.js --v5 /var/ossec/etc/rules                        # Wazuh 5.0 readiness (see below)

Exit code: 2 something stops the manager, 1 rules will be ignored, 0 nothing found.

Related MCP server: dr-mcp

MCP server

{ "mcpServers": { "wazuh-rule-precheck": { "command": "node", "args": ["/path/to/wazuh-rule-precheck/mcp-server.js"] } } }

Tools: wazuh_rule_precheck (files, wazuh_version) and wazuh_v5_readiness (files).

Or in Docker (stdio, runs with no network):

docker build -t wazuh-rule-precheck .
docker run -i --rm --network none wazuh-rule-precheck

Offline, read-only, no credentials. A Claude skill is in SKILL.md.

What it checks (Wazuh 4.x)

Load order matters: Wazuh loads the stock rule files and your files from etc/rules together, sorted by file name, and a parent must already be loaded when its child is read. etc/rules/0010-my_rules.xml with <if_sid>5715</if_sid> is ignored, because it sorts before 0095-sshd_rules.xml; the same rule in local_rules.xml loads.

How it was checked

Each finding was produced first by the real wazuh-analysisd -t 4.14.7 on a test file, then predicted from the same file: 15 cases, 15 matches (node test/test-calib.js, cases in test/cases/). That includes how if_group matches: a case-insensitive substring of a loaded rule's groups, with | alternatives and ^ anchors, the way OS_WordMatch does it.

On the public SOCFortress Wazuh-Rules set (69 rule files, 6 decoder files), wazuh-analysisd -t printed 52 warnings of these kinds and this tool found 55. The 3 extra are real: wazuh-analysisd keeps only the last 50 load messages (ERRORLIST_MAXSIZE 50 in src/analysisd/logmsg.h, oldest dropped first). With 60 broken rules in one file, -t and ossec.log named only the last 25 (test/cases/cap50). On a large ruleset, some ignored rules never show up in the logs.

Wazuh 5.0 readiness (--v5)

Wazuh 5.0 does not load XML rules or decoders and ships no converter. --v5 lists, per rule and decoder, the elements that the 5.0 migration guides (wazuh/wazuh v5.0.0-beta5, docs/guide/migration/rules-4x-to-5x.md and xml-decoders-migration.md) mark as unsupported: rule chaining (if_sid, if_group, if_level), correlation (frequency, if_matched_*, same_*), CDB <list>, <time>, pcre2, <plugin_decoder>, <accumulate/> and others. Based on the 5.0 migration guide, not run on a 5.0 engine. A pre-release can change before GA.

Limits

It knows only the files you give it and the stock ruleset index for the chosen version (4.14.7 for now). Rules in files you did not pass are invisible to it. It does not run Wazuh: it does not test regex syntax, decoder extraction, CDB lists (7616), rule matching on real events, or whether a rule ever fires. Stock groups are treated as always loaded.

Data

data/stock-4.14.7.json holds metadata only: stock rule file names and the rule IDs in each, rule group names, decoder names, and the list of static field names. It was extracted from the ruleset/ directory of wazuh/wazuh at tag v4.14.7; the static field list comes from src/analysisd/rules.c at the same tag. The Wazuh ruleset is © Wazuh, Inc. and licensed under GPLv2. No rule or decoder text (regex, match, description) is copied into this repository.

License

Apache-2.0 for the code in this repository. See LICENSE.

Built by Dong Nguyen, ATK New Technology. If a rule still does not do what you need, we fix Wazuh rules for people who run it: https://atkvn.com/wazuh-rule-precheck.html