diff --git a/man/tallow.1.md b/man/tallow.1.md index 6032353..86bab3d 100644 --- a/man/tallow.1.md +++ b/man/tallow.1.md @@ -48,7 +48,7 @@ the `-DDEBUG=1` symbol passed to the compiler. ## SEE ALSO -systemd-journald(1), iptables(1), ipset(1), tallow.conf(5) +systemd-journald(1), iptables(1), ipset(1), tallow.conf(5), tallow.patterns(5) ## BUGS diff --git a/man/tallow.conf.5.md b/man/tallow.conf.5.md index 79edacd..6e2eb3f 100644 --- a/man/tallow.conf.5.md +++ b/man/tallow.conf.5.md @@ -87,7 +87,7 @@ Use the following commands if you're using firewalld(1): ## SEE ALSO -tallow(1) +tallow(1), tallow.patterns(5) ## AUTHOR diff --git a/man/tallow.patterns.5.md b/man/tallow.patterns.5.md new file mode 100644 index 0000000..8baab93 --- /dev/null +++ b/man/tallow.patterns.5.md @@ -0,0 +1,134 @@ +## tallow.patterns + +Tallow pattern matching configuration files. + + +## SYNOPSIS + +tallow(1) uses regular expressions to match journal entries and extract an IP +address from them. JSON files are used to configure the patterns and banning +thresholds used by tallow(1). + +`/etc/tallow/*.json` +`/usr/share/tallow/*.json` + + +## DESCRIPTION + +tallow(1) uses regular expressions to match journal entries and extract an IP +address from them. JSON files are used to configure the patterns and banning +thresholds used by tallow(1). This adds the ability to extend the patterns +tallow(1) will recognize. Many JSON files can exist for logical grouping. The +tallow(1) daemon will read all JSON files in the configuration directories at +startup. + +tallow(1) operates with default pattern definitions +in`/usr/share/tallow/*.json`. Users can add more patterns with their own JSON +files under `/etc/tallow`. The default JSON files can be overridden by creating +the same file under `/etc/tallow`. + + +## FILE FORMAT + +Pattern configuration files use the JavaScript Object Notation (JSON) format. + +The JSON must be two levels deep and all properties are required. The root +object is an array containing objects with a `filter` key and an `items` key. + +* `filter` is a string that defines a field for filtering the journal file. + This helps make sure patterns are only matched to a subset of journal + entries. See systemd.journal-fields(7) for valid journal fields. + +* `items` is an array of objects that contains three elements: `ban`, `score`, + and `pattern`. + + * `ban` is an integer that defines the number of seconds to ban originating + IP for. If this value is > 0, the IP address get banned immediately when a + journal entry matches `pattern`. + + * `score` is a double that defines a value to add to the accumulated "score" + of an originating IP address each time a journal entry matches + the `pattern`. If the combined score is > 1.0, tallow bans the originating + IP for the default time of 1 hour. The `ban` element value above is not + used for bans made due to `score`. + + * `pattern` is a string that defines a Perl Compatible Regular Expressions + (PCRE) to match against the filtered journal entries. The PCRE should + extract exactly one substring: the originating IP address for tallow(1). + See systemd.journal-fields(7) for valid journal fields. + + + +## EXAMPLES + +1. The JSON below is a snippet from one of the default pattern configuration + files for blocking certain failed `sshd` connections. + + The first pattern will ban an IP address after it fails to login 6 times + causing it to reach a total score > 1.0. + + The second pattern will ban an IP address for 10 seconds every time a login is + attempted with an invalid user. Additionally, it will ban the IP address for + 1 hour if it attempts to login with an invalid user 6 times causing it to + reach a total score > 1.0. + + See the `/usr/share/tallow/sshd.json` file for more `sshd` examples. + + ``` + [ + { + "filter": "SYSLOG_IDENTIFIER=sshd", + "items": [ + { + "ban": 0, + "score": 0.2, + "pattern": "MESSAGE=Failed .* for .* from ([0-9a-z:.]+) port \\d+ ssh2" + }, + { + "ban": 10, + "score": 0.2, + "pattern": "MESSAGE=Invalid user .* from ([0-9a-z:.]+) port \\d+" + } + ] + } + ] + ``` + + + +2. The JSON below defines a pattern for blocking connections based on error logs + from `nginx-mainline` if placed in a `/etc/tallow/nginx-mainline.json` file. + + The pattern will ban an IP address for 15 seconds every time it attempts to + access a script that does not exist. Additionally, it will ban the IP + address for 1 hour if it attempts to access invalid scripts 4 times causing + it to reach a total score > 1.0. + + ``` + [ + { + "filter": "SYSLOG_IDENTIFIER=nginx-mainline", + "items": [ + { + "ban": 15, + "score": 0.3, + "pattern": ".Primary script unknown. while reading response header from upstream, client: ([0-9a-z:.]+)," + } + ] + } + ] + ``` + +## SEE ALSO + +tallow(1), tallow.conf(5) + +## BUGS + +`tallow` is `NOT A SECURITY SOLUTION`, nor does it protect against random +password logins. An attacker may still be able to logon to your systems if you +allow password logins. + +## AUTHOR + +Auke Kok