Security Response

The unexpected raid and resulting death of Osama Bin Laden shocked the world. As always, spammers were quick to jump on this headline and send a variety of spam messages leveraging the event. The “Fallout from the Death of Osama Bin Laden” section includes samples of some of the spam monitored in different languages.

The effect of the Rustock shutdown from the previous month continued this month. After falling 27.43 percent in March, the average daily spam volume fell another 5.35 percent in April. Compared to a year ago , it is down 65.42 percent. Overall, spam made up 74.81 percent of all messages in April, compared with 74.68 percent in March. Going back a year, the percentage of spam was 89.22 in April 2010.

To find out more, click here to download the May 2011 State of Spam & Phishing Report, which highlights the...

When Brian Krebs posted a report about Rustock botnet takedown, Symantec observed a decline in overall spam traffic. Symantec.cloud posted a blog about this, and the Wall Street Journal is now reporting that Microsoft led this takedown.

On March 16, Symantec saw global spam drop 24.7% compared to March 15. On March 17, global spam volume dropped another 11.9% compared to March 16. Compared to a week prior, the volume on March 17 was down 40.4%.

As we typically see with a drop in global spam volume, the overall spam percentage saw a similar decline when spam volume fell. The increase seen on...

In this blog published in January, we followed-up on the spam volume saga as the Rustock botnet returned to action on January 10. At the time, it looked like the holidays were over for spammers. Did the prediction hold up?

Yes, as it turns out. Over the following six weeks, the global spam volume has remained more or less flat. Towards the end of February however, it is showing a bit of a decline.

A similar pattern can be seen for the global spam percentage:

Even though the spam volume has somewhat recovered, it is nowhere near what it was one year ago. This chart shows the global spam volume in the month of February in 2010 and 2011:

全世界でのスパム量については、これまで何カ月も一貫して取り上げてきましたが、減少がとうとう止まったようです。スパム量の前月比は、1 月に再び減少しましたが、これは年初 10 日間だけ見られた Rustock ボットネットの停止が最大の原因でした。2 月には、2010 年 8 月以降初めて前月比スパム量が増加に転じるだろうと、シマンテックでは予測しています。スパムが全メッセージに占める比率は、昨年 12 月には 81.69%、1 月には 79.55% でした。

さらに詳しい情報については、こちらをクリックして 2011 年 2 月号の『スパム & フィッシングレポート』を参照してください。2 月号では以下のトレンドについて説明しています。

•    Conclusion of Spam Volume Saga（スパム量に関する定説の結論）
•    Turmoil in Egypt Shuts Down the Spammers（エジプト争乱によるスパマーの活動停止）
•    Scammers Seek Support for Serrana Flood Victims（セハナ大洪水の被災者支援を騙る詐欺師たち）
•    Big Brother Brasil Bait is Back（「ビッグブラザーブラジル」詐欺の再来）
•    January 2011: Spam Subject Line Analysis（2011 年 1 月、スパム件名の分析）

* 日本語版セキュリティレスポンスブログの RSS フィードを購読するには、...