Current Trends in Mobile-Phone Spam and
Counteractions by NTT DoCoMo
NTT DoCoMo, Inc.
Shinichiro Takahashi
July 7, 2004
THE SPAM PROBLEM
Spam enquiries
to DoCoMo
(1,000)
120
i-mode
subscribers
(million)
50
i-mode
subscribers
40
30
100
80
Spam
Spam problem
problem got
got
serious
in
2001
serious in 2001
with
with more
more than
than 20
20
million
million
subscribers
subscribers
Spam enquiries to DoCoMo
De
cr
20
ea
si
ng
60
40
10
20
0
0
2000
2001
2002
2003
2004
Source: NTT DoCoMo,
DoCoMo, Inc.
-1-
i-mode SPAM
Two major types of spam to i-mode subscribers are:
Advertising
dubious dating sites
Demanding payment for
fictitious invoices
Title: Looking for a date?
From: smile@xxx.xxx
Address smile・・・@・・・
Title
ドキドキしたいとき
"電車で見かける素敵な彼（＾。＾）
街で見かけたアノ娘（＾?＾)みんな
このメール? 見てるかも(?? ?)
出逢い? ? はい つ も スマイル
（＾?＾)
http://www.・・・・・・
女性はもちろん 完 全 無 料 男
性は５０ポイント分サービスです
Visit our site if you’re looking for a
handsome boy or a pretty girl.
http://www.xxx.xxx
No charge for girls, 50 free points
for boys!
Title: Final Notice
From: Billing Dept.
You have not paid the amount of xxx yen
for the site usage fee. Make sure to transfer
money to the following bank account by
1:00 p.m., Feb. 2, 2004.
XXX Bank No.00000
If you refuse to make the payment, you will
be charged six times as the amount
mentioned in this notice.
Contact us at: 06-xxxx-xxxx
z Invitation to access site
z URL to malicious site provided
Address 料金管理課
Title
最終通告
当方はメールサーチ内の有料サイト
課金管理部です。貴殿が観覧した観
覧料金（掲示板記載代含）１７９８０円
(無料ポイント超過分)が未納となって
おります。２月２日午後１時迄に大至
急ご入金ください。
振込先Ａ銀行　Ｂ支店（普）××××。
尚、今回入金無き場合地方の債権
回収業者に貴殿の債権を延滞金を
付け約６倍の金額で債権譲渡させて
頂きますのでご注意ください。
連絡先は06-××××-××××
z Intimidating language
z Bank account details and/or
telephone number provided
-2-
DUBIOUS DATING SITE
BUSINESS MODEL/ PROFIT STRUCTURE
Site operators make huge profits by using “decoys” to deceive
subscribers to become paying members.
Business Model
Profit Structure
Site usage fees
Spam
outsourcing
TransTransmitters
• Operational cost of 10K
EURO generates profits
of 50K EURO
A．Advertising mail
z “Free points provided”
z “Better change of meeting”
• Most operators run
some dozens of similar
sites
B．Invitation mail
z “Let’s get together”
Site
operators
Subscribers
Hiring
C．Reply
z “I really want to see you
（＾。＾）.”
“Decoy”
A
A decoy
decoy keeps
keeps communicating
communicating
with
a
paying
member
with a paying member until
until free
free
points
points are
are used
used up.
up.
-3-
SPAM IS THE MOST COST-EFFECTIVE
ADVERTISEMENT
Delivery Cost
(€cent/mail or copy)
40
26
30
20
10
0.3 to 2
0
3.75
3.75
SMS
from
Mobile
Advertisement
on dating
magazine
0.006
E-mail
from
PC
Source: NTT DoCoMo,
DoCoMo, Inc.
E-mail
from
Mobile
DM
Spam
-4-
INDUSTRY STRUCTURE
Address
list
developers
Bulk mail
Sell lists
Valid
addresses
Site
operators
...
Internet
Sell lists
Transmitters
DoCoMo
server
(i-mode
Centre)
i-mode
subscribers
Spam
Request
spamming
Spam
...
...
Mobile
phones
Access to sites
-5-
COUNTERMEASURES AGAINST ADDRESS LIST DEVELOPERS
DoCoMo constantly develops measures against progressive technology of
address list developers.
2001
2002
Collected address info
from Web sites, etc.
Bulk mail via Internet
Address
Address
List
List
Developers
Developers
Generated
telephone
number
addresses with
MS Excel.
Developed
software for
generating short
addresses.
Collected addresses from Web
sites, etc., automatically and
manually.
• Claimed for damage compensation of
approximately 50K € (Jun. 2002)
・ Encouraged users to change from telephone
number to alphanumeric address (Apr.2001)
・ Provided default address using 20 characters
(Jul. 2001)
2004
(Year)
Resumed bulk mail
・Developed software generating
long, complicated addresses.
・Improved transmission capacity.
(Transmission engine capable of
2 million mailmail-outs per hour)
Enhanced blocking
capability to eradicate
bulk mail to invalid
addresses
(since Dec. 2003)
Blocked bulk mail to invalid
addresses (Nov. 2001)
DoCoMo
DoCoMo
2003
・ Alerted users of the risk of listing their addresses
on Web sites, catalogs and etc.
・ Filed the first lawsuit in Japan to seek suspension
of mail transmission (Oct. 2001)
-6-
COUNTERMEASURES AGAINST TRANSMITTERS
DoCoMo continues to take effective actions against transmitters who are
trying all possible means.
2004
2003
Up to 2002
(Year)
Spam from PCs
Spam from mobile phones
Transmitters
Transmitters
E-mail
spam
...
・ Provided filtering by
specifying domains
(Jan. 2002)
DoCoMo
DoCoMo
・ Provided rejection/receipt
features by specifying
addresses (Nov. 2000)
・ Introduced selective receipt
feature for 3G (May 2001)　SMS
spam
E-mail
spam
...
...
• Deactivated mobiles phones used
・ Deactivated mobile phones
for e-mail spam (since Jul. 2003)
used for SMS spam
• Set the limit of transmission to
(since May 2004)
1,000 messages per day/phone
・ Increased the number of
(Oct. 2003)
specifiable domains for
• Provided rejection of mobilefiltering (May 2004)
generated bulk mail exceeding the
limit of 200 messages (Jan. 2004)
・ Provided filtering by specifying
carriers other than DoCoMo (Dec. 2003)
・ Offered selective receipt feature for
2G　(May 2003)
-7-
PROMOTING SPAM PREVENTIVE PROGRAMS FOR
i-mode USERS
◆　Advertising filtering/rejection features
9　Provide preventive information on DoCoMo’s home page.
9　Describe preventive features on product pamphlets and catalogs.
9 Prepare anti-spam pamphlets focusing on preventive measures to be delivered
at mobile phone shops.
◆　Support activities for anti-spam promotion
9 Give “mobile phones lessons” to show how to use preventive features
(at approximately 1,300 DoCoMo shops).
9 Offer support activities, such as setting for rejection, at mobile phone shops.
9 Send DMs to users who have not used preventive features. ◆　Reducing users’ costs
9　Introduced free packet services (since Aug. 2001).
・ No packet charge for setting rejection and changing address
・ No packet charge for receiving 100 messages per month (applicable to 2G)
-8-
FUTURE ISSUES
Spam
Spam
Spam
Spam
ア
Spam
International
Internationalcooperation
cooperationis
isessential
essentialfor
forself
selfregulations
regulationsand
and
legal
.
legalactions
actionsagainst
againstspam
spam.
••ISPs
’ greater
’ lines
ISPs’
greatereffort
effortto
tosuspend
suspendtransmitters
transmitters’
lines
••Continued
Continuedpursuit
pursuitof
oflegal
legalremedies
remedies(e.g.
(e.g.the
theclaim
claimfor
fordamage
damagemade
madeby
byDoCoMo)
DoCoMo)
••Establish
Establisheffective
effectivelegal
legalframeworks
frameworks
-9-