Technology Overview
Fortinet takes a comprehensive and multi-layer approach and uses a number of
filtering techniques to detect and filter spam.
- Global filters. Through the FortiGuard distribution network,
FortiGuard AntiSpam service provides two databases, namely FortiIP and
FortiSig, as global filters.
FortiIP is a sender IP reputation database while
FortiSig is a spam signature database. These global filters are
constantly updated and enable our FortiGate, FortiClient and FortiMail
products to detect and filter most prevailing spam in the Internet.
- Customized filters. Various customized spam filters
are provided to compliment the Fortinet's AntiSpam
solution on the service delivery units: FortiGate, FortiClient and
FortiMail. These customized filters range from banned words filters,
local white and black lists of
sender email address, heuristic rules, to
highly sophisticated techniques such as Bayesian training in FortiMail.
See the documentation of respective products for more information.
- Dedicated service team. To complete Fortinet's
AntiSpam solution and provide our customer with best in class AntiSpam
service, our dedicated service team of engineers and analysts is
committed to respond to and resolve any false positive report and
other issues in 24 hours, monitor and analyze latest spam
techniques, continuously update FortiIP and FortiSig databases, and research
and design new spam filters.
FortiGuard AntiSpam Service filters include FortiIP and FortiSig database.
FortiIP is a sender IP reputation database,
and FortiSig is a spam signature database containing three types of signatures:
FortiSig1, FortiSig2 and FortiSig3.
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- FortiIP - sender IP reputation database.
- Most of spam is presently sent from mis-configured or virus-infected hosts.
FortiGuard AntiSpam Service maintains a global IP reputation database
where the reputation of each IP is built
and maintained based on tens of properties of
this IP address gathered from various sources. The properties of an IP
address include its whois information, geographical location, its
service provider, whether it is an open relay or hijacked host, etc.
One of the key properties used to maintain the reputation is the email
volume from this sender as gathered from our FortiGuard service
network. By comparing a sender's recent email volume with its
historical pattern, FortiGuard AntiSpam Service updates each IP's
reputation in real-time and provides a highly effective sender IP address
filter.
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- FortiSig1 - spamvertised URLs.
- About 90% of spam
has one or more URLs in the message body. These URLs link one to
spammers' website promoting their products and services. In the
phishing spam, these URLs direct one to a fake bank or other financial
institution's website preying for private financial information.
FortiGuard AntiSpam Service collects spam samples through our global
spam trap network and spam sample submissions from our customers and
partners. The URLs are then extracted from the spam samples and went
through our rigorous QA process before being injected the FortiSig
Database. The URLs are then subject to the continuous aging process
where obsolete ones are removed promptly.
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- FortiSig2 - spamvertised email addresses.
- Similar
to the spamvertised URLs, lots of spam have an email address in the
message body that prompts one to contact the spammers. By extracting
these email addresses from the spam sample, these spamvertised email
addresses provide another powerful global filter to identify and
filter spam.
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- FortiSig3 - spam object checksums.
- In line with the
release of FortiOS 3.0, FortiGuard AntiSpam Service releases one
additional global filter as FortiSig3 to counter attack those
hard-to-detect spam that do not contain FortiSig1 or FortiSig2. Using a
proprietary algorithm, objects in spam are identified and a fuzzy
checksum is calculated from each object. The object can be part of the
message body or an attachment. The checksum is then added into the
FortiSig database, providing another highly effective global filter
with virtual no false positives.
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- FortiRule - dynamic heuristic rules.
- This is the latest component offered in the FortiGuard Antispam Service,
available in FortiMail version 3.0 MR1 and later. This global filter uses
dynamically updated heuristic rules to identify spam, exploiting various
attributes in the spam message header, body, mime header, and attachments.
With manually crafted heuristic rules for specific spam attacks, FortiRule
further increases the catch rate with virtually no false positives.
Definition of Spam
To judge an email message as spam is quite subjective. Most people
easily agree on some email message as being spam, such as the never
ending messages of Viagra ads and Nigeria scam messages. Some may
include all advertisements and newsletters as spam, others may consider
newsletters as legitimate email.
FortiGuard use the industry standard's
definition of spam as Unsolicited Bulk Email (UBE). Unsolicited means
that the Recipient has not granted verifiable permission for the
message to be sent and the sender has no discernible relationship with
all or some of the recipients. Bulk means the message is sent as part
of a larger collection of messages, all having substantively identical
content.
A message is considered spam if both
Unsolicited and Bulk. Unsolicited Email can be normal email, such as
first contact enquiries, job enquiries, and sales enquiries. Bulk Email can
be normal email, such as subscriber newsletters, customer
communications, discussion lists. The message content is generally
irrelevant in determining whether a message is spam though most are
commercial in nature. There is spam that fraudulently promotes penny
stocks in the classic pump-and-dump scheme. There is spam that promotes
religious beliefs.
Technically, an email message is spam if
- The recipient's personal identity and context are irrelevant because
the message is equally applicable to many other potential recipients;
- And, the recipient has not verifiably granted deliberate, explicit,
and still-revocable permission for it to be sent.
Submit Spam
Spam submitted will be analyzed, their signatures will be extracted
and added to our spam signature database, which makes FortiGuard
AntiSpam detecting and filtering similar spam.
We appreciate your submitting spam samples, but do not respond to them
because of the volume.
Submission Instructions:
For Microsoft Outlook:
- Method 1:
-
- Open Microsoft Outlook
- Create a new email to
submitspam@fortinet.com
- Drag the message(s) you want to submit from the "message listing"
pane into the body of the new message window you just created.
- Send the message.
- Method 2:
- Set Outlook to forward email as original attachment by
- In Outlook menu, click "Tools" -> "Options"
- In "Preference" tab, click "Email Options..."
button in "Email" section
- In the drop-down section "When forwarding a message,"
choose "Attach original message text"
- Click "OK"
From now on, you can simply click "Forward" button in Outlook and put
submitspam@fortinet.com
to "To:" address to submit a spam.
For Microsoft Outlook Express:
-
-
- Open Microsoft Outlook Express
- Right-click the message you want to submit,
click "Forward As Attachment"
- Put
submitspam@fortinet.com to "To:" address
- Click "Send"
For Thunderbird/Mozilla/Netscape:
- Method 1:
-
- Open Thunderbird/Mozilla/Netscape mail
- Create a new email to
submitspam@fortinet.com
- Drag the message(s) you want to submit from the "message listing"
pane into the 'attachment' area of the new message window you just
created.
- Send the message
- Method 2:
- Set Thunderbird/Mozilla/Netscape to forward email as original attachment by
- Click "Edit" -> "Preference"
- In Composition section, there is a drop-down option for
"Forward messages". Choose "As Attachment".
- Click "OK"/"Close"
From now on, you can simply click "Forward" button in
Thunderbird/Mozilla/Netscape and put
submitspam@fortinet.com
to "To:" address to submit a spam.
Web-based Email:
-
- If you are using web-based mail like yahoo, please forward the spam
email as attachment instead of inline text.
Notes:
- Due to the volume of the spam submitted,
we do not respond to any spam submitted.
Submit False Positive
If you notice a false positive, a clean message marked as spam by
FortiGuard AntiSpam Service, or if you believe an IP address, URL,
or email address is blacklisted incorrectly, you can either:
If you are the email sender who had an email message incorrectly blocked:
- Send us the error message you received.
The error message shall look like this:
-
mail.xxx.xxx #5.7.1 smtp;554 5.7.1 This message has been blocked
because it contains
FortiGuard - AntiSpam blocking URL/IP(s).(black url/ip xxx.xxx)
If you are a Fortinet customer:
- Send us the AntiSpam log messages obtained from FortiGate,
FortiClient or FortiMail, including your Fortinet product's serial number.
The AntiSpam log from FortiGate shall look like this:
-
Feb 26 19:15:13 xx.xx.com date=2006-02-26 time=19:15:14
device_id=FGT-xxxxxxxxxxx log_id=xxxxxxx type=emailfilter subtype=smtp
pri=notice vd=root src=xxx.xxx.xxx.xxx dst=xxx.xxx.xxx.xxx src_int=wan1
dst_int=internal service=smtp status=detected from="xxx@xxx.com"
to="xxxx@xxx.net" msg="The email contains FortiGuard - AntiSpam
blocking URL(s).(black url xx.xxxx.xxx)"
Contact Us
Please send any questions or concerns to:
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