The new stable versions of Rspamd and Rmilter have been released: 1.3.4 and 1.9.2 accordingly. There are a couple of improvements and some important bugfixes. Please note that in the unlikely case you have used regexp rules in Rmilter then you SHOULD NOT upgrade Rmilter and file a bug report (however, I’m pretty sure that it’s not used by anybody since it hasn’t ever been documented). Here is a list of notable changes in Rmilter and Rspamd.

Rspamd reload command has been fixed

It is now possible to gracefully reload Rspamd configuration by sending HUP signal or by using reload subcommand for the init scripts. Graceful reload is useful when it’s required to update configuration without stopping email processing. During this process, Rspamd starts a new worker processes with the new configuration whilst the existing ones process the pending messages.

Better ASN/country support

ASN/country detection module has been split from the ip_score module allowing use of this data in other modules, for example, in the multimap module to match maps based on country or ASN.

Variable maps in the multimap module

It’s now possible to create maps based on the results of other Lua or internal Rspamd modules. This is particularly useful to link different modules with mulitmap.

DNNSEC stub resolver support

It’s now possible to enable DNSSEC checks in Rspamd through use of a DNSSEC compatible recursive resolver (e.g. Unbound) and check for DNSSEC authentication results in Lua DNS module.

DMARC and DKIM module fixes

There are some important fixes for DMARC and DKIM modules in this version of Rspamd that are related to canonicalization in DKIM and subdomains policies in DMARC.

Redis backend configuration

Now Redis backend in the statistical module can use the global redis settings similar to other modules.

Tasks checksums

Each task and each MIME part now has its own checksum that could be used to detect the same message or the same attachment.

DKIM signature header is now folded by Rspamd

Since DKIM signature header might be quite long, Rspamd now folds it to fit 80 characters wide common for MIME messages.

Ratelimit module fixed

This release of Rspamd fixes a regression introduced in 1.3.3 which prevented the ratelimit module from working properly.

Fixed X-Forwarded-For header processing

Processing of X-Forwarded-For header in the controller has been fixed.

Rmilter configuration improvements

It is now possible to use += operator to append elements to Rmilter lists (e.g. whitelists) and = to redefine the parameter completely. Hosts lists now can contain hostnames along with IP addresses. List parameters can now be empty to clear lists that are non-empty by default. DKIM signing can be completely disabled in the configuration.

Rmilter regexp rules are removed

Support for regexp rules has been removed from Rmilter. This is an old feature which has never been documented nor used by any users. It was likely broken so I have decided to remove it from Rmilter completely to simplify configuration parser and the overall processing logic. If you are using it then do not update Rmilter and please file a bug report in the GitHub issue tracker.

Rmilter bugfixes

Unconditional greylisting support is now restored in Rmilter. Headers added or removed by Rspamd are now treated by Rmilter correctly.

The new stable version of Rspamd is available: 1.3.3. This release includes a couple of critical bugs fixes and important improvements. We recommend to update Rspamd to version 1.3.3 as soon as possible due to a serious error in fuzzy hashes processing.

Important fuzzy hashes incompatibility

There was a serious bug in fuzzy check plugin when using transport encryption and the default fuzzy key. Since encryption is enabled in the default configuration, all users should consider updating their Rspamd packages. Another important consequence of this bug is that the private fuzzy storages should be relearned because of a wrong key used for hashing. To summarize, here is a list of issues for different types of fuzzy storages:

1. For private fuzzy storages that are used without encryption_key nothing has changed and everything should work as desired
2. For storages with explicit fuzzy_key everything should work as desired with the exception of attachments hashes: they no longer use custom fuzzy_key for performance and architecture reasons. So it is recommended to relearn such a storage after upgrading to 1.3.3
3. For storages without explicit fuzzy_key but with encryption_key the recommended action is to upgrade to 1.3.3 and relearn a storage since all old hashes won’t be recognized (there won’t be any false positive hits however).

Rspamd.com fuzzy storage has changed hashing algorithm

Users of rspamd.com storage should either use the provided default configuration for fuzzy_check plugin or update their custom configuration to include the following line in the rule for rspamd.com storage:

rule "rspamd.com" {
  algorithm = "mumhash";
  # The rest of the configuration
}

The default rule provided by Rspamd distribution is now the following:

rule "rspamd.com" {
  algorithm = "mumhash";
  servers = "rspamd.com:11335";
  encryption_key = "icy63itbhhni8bq15ntp5n5symuixf73s1kpjh6skaq4e7nx5fiy";
  symbol = "FUZZY_UNKNOWN";
  mime_types = ["application/*"];
  max_score = 20.0;
  read_only = yes;
  skip_unknown = yes;
  fuzzy_map = {
    FUZZY_DENIED {
      max_score = 20.0;
      flag = 1;
    }
    FUZZY_PROB {
      max_score = 10.0;
      flag = 2;
    }
    FUZZY_WHITE {
      max_score = 2.0;
      flag = 3;
    }
  }
}

Failure to update hashing algorithm will cause Rspamd not to find any hits in the rspamd.com storage.

Support for Redis maps in the Multimap plugin

There is now Redis support in the Multimap plugin. With this feature you can create maps that can be easily scaled and frequently modified. For example, you could use it for temporary records that work as DNS blacklists but using Redis storage.

Hyperscan cache important fix

This version contains an important fix for Hyperscan caching inconsistency. After rules change, there were no checks against sanity of regexp ids stored in the cache. In turn, that caused random regexps misdetections and false positive detections. In version 1.3.3 Rspamd checks every single ID using checksum and recompiles the whole cached file when a checksum is invalid.

SARBL URL black list support has been added to the default configuration

Rspamd now will check URLs using SARBL list to detect bad or phishing domains in messages.

Lua API improvements

There are number of improvements in Lua API shipped with Rspamd:

• util.get_tld function has been fixed to find the longest possible TLD
• rspamd_url now allows initialization of the library and provides a simpler API to parse URLs in strings
• rspamd_cryptobox now provides a one step hashing API
• util.strequal_caseless function now works as intended
• rspamd_redis now returns nil for data when Redis returns NIL (e.g. when a key is not found)
• rspamd_http now always performs DNS request even when maximum number of DNS requests for a message has been reached

Prefilters and postfilters registered in Rspamd are now executed in order defined by their priority:

• Prefilters with higher priority are executed first
• Postfilters with higher priority are executed last

The next stable version of Rspamd, 1.3.2, is now available. It contains many improvements, bug fixes and another integration method: Communigate Pro helper. Here are the main improvements added in this version:

Important bug fixes

There was a bug introduced in 1.3.0 related to multiple value header processing which broke, for instance, the processing of multiple SMTP recipients. This issue has been fixed in 1.3.2.

Attributes in HTML tags are now HTML decoded to avoid polluting other elements.

The last element in DMARC records is now correctly parsed.

Hfilter module has been reworked to reduce false positive hits rate for hostnames and SMTP helo values.

SPF plugin features

Rspamd now recognizes DNS failures when resolving SPF records and abstains from caching failed lookups. There is now a new symbol R_SPF_DNSFAIL that is inserted when there was a DNS error during resolving of a SPF record. Furthermore, Rspamd will not insert R_SPF_DENY if there was an error looking up records required by policy.

Better HTML support

There are a couple of features and important bugs fixes for HTML parser introduced in Rspamd 1.3.2. There is new HTML block elements parser that can deal with colors in HTML documents and, in particular, with named colors. Secondly, parsed HTML tags now contain the length of the content enclosed within the tag. And finally, the Lua API is improved with a new foreach_tag method that allows traversing across particular HTML tags examining their content. The existing HTML related rules are updated accordingly to deal with HTML spam better using the new API.

Improved settings matches for authorized users

It is now possible to match any authorized user when applying user settings. It might be useful for applying different settings to authenticated users:

outbound {
  priority = high;
  id = "outbound";
  authenticated = true;

  apply {
    groups_disabled = ["hfilter", "spf", "dkim", "rbl"];
  }
}

Redis integration fix

Rspamd no longer uses the KEYS pattern* command for getting statistics. It was found that this command literally kills Redis performance on large data sets. This mechanism has been reworked to avoid KEYS command.

DKIM support improvements

DKIM signing has been fixed with additional tests added. rspamc utility can now use a DKIM signature header passed by Rspamd to sign email in --mime mode. DKIM header folding issues have been found and fixed in Rspamd 1.3.2.

URL detection fixes

Rspamd now tries to search for a longest possible suffix when matching TLD parts to distinguish between common suffixes of different length, for example .net and .in.net.

We have released new updates for Rspamd and Rmilter: 1.3.1 and 1.9.1 accordingly. There are a couple of important bugfixes and some useful new features in these releases.

Systemd activation has been removed from Rspamd and Rmilter

Over the recent years, we have experienced constant issues reported by users about Systemd socket activation. This feature seems to be completely broken in systems with both IPv4/IPv6 enabled. Moreover, it seems to be harmful as Rspamd setup time is quite significant whilst socket activation is mostly intended for interactive on-demand daemons. Socket activation has been added under the pressure of Debian packaging rules, though Rspamd is completely rotten in Debian official repos and we strongly discourage Debian users from using the official Debian packages. While we are still looking for a new Debian maintainer for Rspamd, I can declare that there will be no sockets activation enabled by default in Rspamd nor Rmilter.

The switch to standalone mode should be transparent for users. The only significant difference is use of rspamd.service instead of rspamd.socket in service management commands. In some cases you might need to restart Rmilter after upgrade (for example, in Debian Jessie):

systemctl restart rmilter.service

Rmilter crash on BSD systems

There was a bug that was caused by use of pthread_specific variables. Unfortunately, libmilter is poorly designed and can destroy or move certain threads which causes horrific errors. Linux is somehow not affected, however, there is still use-after-free bug with this approach. In Rmilter 1.9.1, this issue has been fixed.

New multimap features in Rspamd

The multimap module has been significantly updated in Rspamd 1.3.1. It now supports maps that are checked conditionally depending on combinations of other symbols. There is now also support for multiple symbols and scores per map. A new hostname map type has been added to support matching of hostnames. Many new tests have been written to cover multimap functions and to provide resistance against regressions.

Greylisting fixes in Rspamd

There are a couple of fixes in the greylisting module, including authenticated users whitelisting, general logic fixes and restoration of selective greylisting.

Critical issue with Catena password scheme

There was a regression in 1.3 that prevented Catena password encryption scheme from being correctly read by the controller. It has been fixed in 1.3.1, so Catena passwords (those with $2$ prefix) could be used again.

Critical fix for Hyperscan cache

There was a race condition when a worker that writes Hyperscan file was killed in the middle of this process. Afterwards, a cache file was left in an inconsistent state which wasn’t detected or corrected on subsequent Rspamd runs. That caused multiple issues with regular expressions processing, including false and failed matches on arbitrary texts. Since 1.3.1, Rspamd strictly ensures that a Hyperscan cache file has been correctly written to the filesystem.

Message size limit in Rspamd

We now limit the incoming size of a message to prevent crashes on insane input. By default, this limit is set to 50Mb, however it can be changed by max_message setting in the options section:

# local.d/options.inc
max_message = 100Mb;

Rspamd configuration files includes logic

From this version, the behaviour of local.d and override.d is consistent with their description: values in local.d add values to the existing configuration overwriting the same keys, and values from override.d overwrites the whole sections. For example, if we have the original configuration that looks like this:

# orig.conf
rule "something" {
  key1 = value1;
  key2 = {
    subkey1 = "subvalue1";
  }
}
rule "other" {
  key3 = value3;
}

and some local.d/orig.conf that looks like this:

# local.d/orig.conf
rule "something" {
  key1 = other_value; # overwrite "value1"
  key2 = {
    subkey2 = "subvalue2"; # append new value
  }
}
rule "local" { # add new rule
  key_local = "value_local";
}

then we will have the following merged configuration:

# config with local.d/orig.conf
rule "something" {
  key1 = other_value; # from local
  key2 = {
    subkey1 = "subvalue1";
    subkey2 = "subvalue2"; # from local
  }
}
rule "other" {
  key3 = value3;
}
rule "local" { # from local
  key_local = "value_local";
}

If you have the same config but in override.d directory, then it will completely override all rules defined in the original file:

# config with override.d/orig.conf
rule "something" {
  key1 = other_value;
  key2 = {
    subkey2 = "subvalue2";
}
rule "local" {
  key_local = "value_local";
}

Other bugfixes and improvements

There are couple of other important bugfixes and improvements including a critical fix for extracting values from the top received header. The test framework has been improved with new functional tests and better integration with CircleCI

Today, we’ve released major updates for both Rspamd and Rmilter: Rspamd is updated to version 1.3 and Rmilter is updated to version 1.9. These updates include many new features, including Rspamd proxy and fuzzy storage mirroring. Here is the list of the most important changes introduced in Rspamd 1.3:

Rspamd proxy support

We understand the importance of testing when building spam filtering engines. Most testing work requires checking with production mail flows. The idea behind Rspamd proxy is to create a lightweight shim that can forward requests to the main Rspamd instance and mirror a certain percentage of mail to some testing environment and compare scan results afterwards. Moreover, Rspamd proxy can encrypt traffic and provide zero-copy forwarding for local connections. You can read more about Rspamd proxy in the media section where there is a link to a presentation that describes proxy features in detail.

Fuzzy storage mirroring

Fuzzy hashes are a powerful method to filter spam mail. In version 1.3, Rspamd supports hash mirroring enabling master-slave replication for different storages. Furthermore, it is possible to organise collections of hashes from multiple sources. The synchronization structure is quite simple but it allows for building distributed systems providing the necessary level of redundancy and security. All these features are described in the fuzzy storage operational guide.

HTTPS maps support

Rspamd now supports HTTPS protocol when accessing HTTP resources. That allows for creation of maps that can query HTTPS resources, for example, there is now support for OpenPhish and PhishTank feeds in the phishing module.

Redis replication support

It is now possible to use Redis cluster in all Rspamd modules, since Redis requests are split between read_servers and write_servers. Another useful addition is the ability to specify Redis servers in a dedicated section to configure all modules that use Redis together. You can read more information about it in the Redis integration guide.

Improved content filtering

There are many features added to the multimap and mime_types plugins.

First of all, Rspamd can now read files list from some archives types, namely, zip and rar. This feature allows to ban some certain bad attachments that could be archived (or even encrypted) by spammers. Since archives are the main source of malware this feature should be extremely useful in filtering these sort of malicious messages. Mime_types plugin is updated to find the following bad patterns:

• archive in archive
• double extension to hide malware (e.g. pdf.exe)
• certain list of blacklisted extensions (user’s configurable)

Secondly, multimap plugin can now scan message content. This allows you to create, for example, regular expressions map (powered by Hyperscan that can filter messages using a a comprehensive list of bad patterns.

There are a couple of other improvements to the multimap module, for example, new filters and map deduplication.

Internal greylisting support

Rspamd can now delay suspicious messages internally. In earlier versions, you would require some external tool (for example, Rmilter) to do this job for Rspamd. Since 1.3, you can do this task just within Rspamd regardless of the integration method you use.

Replies module

Similarly to the previous module, this Rmilter feature is now available within Rspamd. By means of this module, Rspamd can store our outgoing email IDs and automatically whitelist external replies to these messages. This feature allows for immediate delivery of replies, automatic notifications and bounces for local users.

DKIM signatures support

Rspamd now supports DKIM signing in addition to DKIM checks. Signing condition is defined by a custom Lua script that allows to select conditions for signing, the appropriate signing key and selector all by using Rspamd Lua API features. There are a couple of examples that are provided in the module’s documentation. rspamadm utility can now generate DKIM key pairs and DNS records for your domains.

WebUI improvements

There are various improvements in the Rspamd web interface. For example, it now includes a throughput graph powered by d3.js and the custom module contributed by Alexander Moisseev. You can now also learn fuzzy using WebUI and there are many bugs and visual issues fixed in this version.

Other changes

Rspamd 1.3 also includes other changes that improve stability, filtering quality and performance, for example faster hash function selection. There are many critical bug fixes that were not backported to the 1.2 branch, for instance, major Redis statistics rework (which can now be used in highly loaded production environments). Many rules have been rescored and reworked. There are also many bug fixes to the URL detection logic and phishing detection. The chartable module has been completely rewritten to provide more useful homograph detection. There are massive changes to the documentation: new guides, better FAQ section and completely reworked Rmilter section.

WARNING: There are a couple of incompatible changes for Rmilter, so please take a look at the migration document.