cyr_virusscan

Scan for viruses using configured virus scanner or manage infected messages using search criteria.

Synopsis

cyr_virusscan [ -C config-file ] [ -s imap-search-string ] [ -r [ -n] ] [-v] [ mboxpattern1 ... ]

Description

cyr_virusscan can be used to invoke an external virus scanner (currently only ClamAV is supported) to scan specified IMAP mailboxes. If no mboxpattern is given, cyr_virusscan works on all mailboxes.

Alternately, with the -s option, the IMAP SEARCH string will be used as a specification of messages which are assumed to be infected, and will be treated as such. The virus scanner is not invoked. Useful for removing messages without a distinct signature, such as Phish.

A table of infected messages will be output.

To remove infected messages, use the -r flag. Infected messages will be expunged from the user’s mailbox.

With the notify flag, -n, notifications will be appended to the inbox of the mailbox owner, containing message digest information for the affected mail. This flag only works in combination with -r. The notification message can by customised by template, for details see Notifications below.

cyr_virusscan can be configured to run periodically by cron(8) via crontab(5) or your preferred method (i.e. /etc/cron.hourly), or by master(8) via the EVENTS{} section in cyrus.conf(5).

cyr_virusscan reads its configuration options out of the imapd.conf(5) file unless specified otherwise by -C.

Note that Cyrus does not ship with any virus scanners: you need to install one separately to make use of it with Cyrus.

Options

-C config-file

Use the specified configuration file config-file rather than the default imapd.conf(5).

-n

Notify mailbox owner of deleted messages via email. This flag is only operable in combination with -r.

-r

Remove infected messages.

-s imap-search-string

Rather than scanning for viruses, messages matching the search criteria will be treated as infected.

-v

Produce more verbose output

Notifications

When the -n flag is provided, notifications are sent to mailbox owners when infected messages are removed. One notification is sent per owner, containing a digest of each message that was deleted from any of their mailboxes.

The default notification subject is “Automatically deleted mail”, which can be overridden by setting virusscan_notification_subject in imapd.conf(5) to a UTF-8 value.

Each infected message will be described according to the following template:

The following message was deleted from mailbox '%MAILBOX%'
because it was infected with virus '%VIRUS%'

    Message-ID: %MSG_ID%
    Date: %MSG_DATE%
    From: %MSG_FROM%
    Subject: %MSG_SUBJECT%
    IMAP UID: %MSG_UID%

To use a custom template, create a UTF-8 file containing your desired text and using the same %-delimited substitutions as above, and set the virusscan_notification_template option in imapd.conf(5) to its path.

The notification message will be properly MIME-encoded at delivery. Do not pre-encode the template file or the subject!

When cyr_virusscan starts up, if notifications have been requested (with the -n flag), a basic sanity check of the template will be performed prior to initialising the antivirus engine. If it appears that the resultant notifications would be undeliverable for some reason, cyr_virusscan will exit immediately with an error, rather than risk deleting messages without notifying.

Examples

cyr_virusscan
Scan all mailboxes, printing report on the screen. Do not remove infected messages.
Using ClamAV virus scanner
Loaded 5789330 virus signatures.

Mailbox Name                                       Msg UID      Status  Virus Name
----------------------------------------        ----------      ------  --------------------------------------------------
user.betty                                          185395        READ  Heuristics.Phishing.Email.SpoofedDomain
user.betty.Bank stuff                                    9        READ  Html.Phishing.Bank-1172
user.betty.Bank stuff                                   10        READ  Html.Phishing.Bank-1172
user.betty.Bank stuff                                   11        READ  Html.Phishing.Bank-1172

Mailbox Name                                       Msg UID      Status  Virus Name
----------------------------------------        ----------      ------  --------------------------------------------------
user.bovik                                           17426        READ  Email.Trojan.Trojan-1051
cyr_virusscan -r -n user/bovik
Scan mailbox user/bovik, removing infected messages and append notifications to Bovik’s inbox.
Mailbox Name                                       Msg UID      Status  Virus Name
----------------------------------------        ----------      ------  --------------------------------------------------
user.bovik                                         17426          READ  Email.Trojan.Trojan-1051
A message like this would end up in bovik’s inbox:
The following message was deleted from mailbox 'INBOX'
because it was infected with virus 'Email.Trojan.Trojan-1051'

    Message-ID: <201308131519.r7DFJM9K083763@tselina.kiev.ua>
    Date: Tue, 13 Aug 2013 18:19:22 +0300 (EEST)
    From: "FEDEX Thomas Cooper" <thomas_cooper94@themovieposterpage.com>
    Subject: Problem with the delivery of parcel
    IMAP UID: 17426
cyr_virusscan -r -n -s 'SUBJECT "Fedex"' user/bovik
Search mailbox user/bovik for messages which have Fedex in the subject line, removing them all, and appending notifications to Bovik’s inbox.
Mailbox Name                                       Msg UID      Status  Virus Name
----------------------------------------        ----------      ------  --------------------------------------------------
user.bovik                                         17185          READ  Cyrus Administrator Targeted Removal (Phish, etc.)
user.bovik                                         17203          READ  Cyrus Administrator Targeted Removal (Phish, etc.)
user.bovik                                         17338          READ  Cyrus Administrator Targeted Removal (Phish, etc.)
user.bovik                                         17373          READ  Cyrus Administrator Targeted Removal (Phish, etc.)
user.bovik                                         19238          READ  Cyrus Administrator Targeted Removal (Phish, etc.)
user.bovik                                         19268          READ  Cyrus Administrator Targeted Removal (Phish, etc.)

History

Virus scan support was first introduced in Cyrus version 3.0.

Files

/etc/imapd.conf