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Parse Cloudflare Logs JSON data

Overview

After downloading your Cloudflare Logs data, you can use different tools to parse and analyze your logs.

In this tutorial, you will learn how to parse your JSON log data using jq. To get started with jq, visit the jq official site.

Aggregating fields

To aggregate a field appearing in the log, such as by IP address, URI, or referrer, you can use several jq commands. This is useful to identify any patterns in traffic; for example, to identify your most popular pages or to block an attack.

The three examples below match on a field name and provides a count of each field instance, sorted in ascending order by count.

$ jq -r .ClientRequestURI logs.json | sort -n | uniq -c | sort -n | tail2 /nginx-logo.png2 /poweredby.png2 /testagain3 /favicon.ico3 /testing3 /testing1236 /test7 /testing123410 /cdn-cgi/nexp/dok3v=1613a3a185/cloudflare/rocket.js54 /
$ jq -r .ClientRequestUserAgent logs.json | sort -n | uniq -c | sort -n | tail1 python-requests/2.9.12 Mozilla/5.0 (Macintosh; Intel Mac OS X 10_7_5) AppleWebKit/537.17 (KHTML, like Gecko) Chrome/24.0.1312.56 Safari/537.174 Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/48.0.2564.116 Safari/537.365 curl/7.47.2-DEV36 Mozilla/5.0 (X11; Linux x86_64; rv:44.0) Gecko/20100101 Firefox/44.051 curl/7.46.0-DEV
$ jq -r .ClientRequestReferer logs.json | sort -n | uniq -c | sort -n | tail2 http://example.com/testagain3 http://example.com/testing5 http://example.com/5 http://example.com/testing1237 http://example.com/testing123477 null

Filtering fields

Another common use case involves filtering data for a specific field value and then aggregating after that. This helps answer questions like Which URLs saw the most 502 errors?. For example:

$ jq 'select(.OriginResponseStatus == 502) | .ClientRequestURI' logs.json | sort -n | uniq -c | sort -n | tail1 "/favicon.ico"1 "/testing"3 "/testing123"6 "/test"6 "/testing1234"18 "/"

To see the top IP addresses blocked by the Cloudflare WAF:

$ jq -r 'select(.WAFAction == "drop") | .ClientIP' logs.json | sort -n | uniq -c | sort -n1 127.0.0.1

Understanding pathing

The three pathing fields stored in Cloudflare Logs are:

  • EdgePathingSrc (pathing source)
  • EdgePathingOp (pathing operation)
  • EdgePathingStatus (pathing status)

EdgePathingSrc refers to the system that last handled the request before an error occurred or the request was passed to the cache server. Typically, this will be the macro/reputation list. Possible pathing sources include:

  • err
  • sslv (SSL verification checker)
  • bic (browser integrity check)
  • hot (hotlink protection)
  • macro (the reputation list)
  • skip (Always Online or CDNJS resources)
  • user (user firewall rule)

For example:

$ jq -r .EdgePathingSrc logs.json | sort -n | uniq -c | sort -n | tail1 err5 user93 macro

EdgePathingOp indicates how the request was handled. wl is a request that passed all checks and went to your origin server. Other possible values are:

  • errHost (host header mismatch, DNS errors, etc.)
  • ban (blocked by IP address, range, etc.)
  • tempOk (challenge successfully completed)
  • chl (challenge issued)

For example:

$ jq -r .EdgePathingOp logs.json | sort -n | uniq -c | sort -n | tail1 chl1 errHost97 wl

EdgePathingStatus is the value EdgePathingSrc returns. With a pathing source of macro, user, or err, the pathing status indicates the list where the IP address was found. nr is the most common value and it means that the request was not flagged by a security check. Some values indicate the class of user; for example, se means search engine. Others indicate whether the visitor saw an error or a captcha, such as, captchaNew or jschlOK.

For example:

$ jq -r .EdgePathingStatus logs.json | sort -n | uniq -c | sort -n | tail1 captchaNew1 dnsErr5 ip92 nr

How does pathing map to Threat Analytics?

Certain combinations of pathing have been labeled in the Cloudflare Threat Analytics feature (in the Analytics app in the Cloudflare dashboard). The mapping is as follows:

PathingLabel
bic.ban.unknownBad browser
hot.ban.unknownBlocked hotlink
hot.ban.ip
macro.ban.ipBad IP
user.ban.ctryCountry block
user.ban.ipIP block (user)
user.ban.ipr16IP range block (/16)
user.ban.ipr24IP range block (/24)
macro.chl.captchaErrCaptcha Error
macro.chl.captchaFailHuman Challenged
macro.chl.captchaNewNew CAPTCHA (CF)
macro.chl.jschlFailBrowser Challenged
macro.chl.jschlNewChallenged threat
macro.chl.jschlErrBot request
user.chl.captchaNewNew CAPTCHA (user)

Understanding response fields

The response status appears in three places in a request:

  • edgeResponse
  • cacheResponse
  • originResponse

In your logs, the edge is what first accepts a visitor's request. The cache then accepts the request and either forwards it to your origin or responds from the cache. It's possible to have a request that has only an edgeResponse or a request that has an edgeResponse and a cacheResponse, but no originResponse.

This is how you can see where a request terminates. Requests with only an edgeResponse likely hit a security check or processing error. Requests with an edgeResponse and a cacheResponse either were served from the cache or saw an error contacting your origin server. Requests that have an originResponse went all the way to your origin server and errors seen would have been served directly from there.

For example, the following query shows the status code and pathing information for all requests that terminated at the Cloudflare edge:

$ jq -r 'select(.OriginResponseStatus == null) | select(.CacheResponseStatus == null) |"\(.EdgeResponseStatus) / \(.EdgePathingSrc) / \(.EdgePathingStatus) / \(.EdgePathingOp)"' logs.json | sort -n | uniq -c | sort -n1 403 / macro / captchaNew / chl1 403 / macro / nr / wl1 409 / err / dnsErr / errHost

Showing cached requests

To see your cache ratios, try the following query:

$ jq -r '.CacheCacheStatus' logs.json | sort -n | uniq -c | sort -n3 hit3 null3 stale4 expired6 miss81 unknown

Showing TLS versions

To see what TLS versions your visitors are using for example, to decide if you can disable TLS versions that are older than 1.2 use the following query:

$ jq -r '.ClientSSLProtocol' logs.json | sort -n | uniq -c | sort -n42 none58 TLSv1.2