Posts Tagged: spam


18
Aug 16

Massive Email Bombs Target .Gov Addresses

Over the weekend, unknown assailants launched a massive cyber attack aimed at flooding targeted dot-gov (.gov) email inboxes with subscription requests to thousands of email lists. According to experts, the attack — designed to render the targeted inboxes useless for a period of time — was successful largely thanks to the staggering number of email newsletters that don’t take the basic step of validating new signup requests.

These attacks apparently have been going on at a low level for weeks, but they intensified tremendously over this past weekend. This most recent assault reportedly involved more than 100 government email addresses belonging to various countries that were subscribed to large numbers of lists in a short space of time by the attacker(s). That’s according to Spamhaus, an entity that keeps a running list of known spamming operations to which many of the world’s largest Internet service providers (ISPs) subscribe.

What my inbox looked like on Saturday, Aug. 13. Yours Truly and apparently at least 100 .gov email addresses got hit with an email bombing attack.

What my inbox looked like on Saturday, Aug. 13. Yours Truly and apparently at least 100 .gov email addresses got hit with an email bombing attack.

When Spamhaus lists a swath of Internet address space as a source of junk email, ISPs usually stop routing email for organizations within those chunks of addresses. On Sunday, Spamhaus started telling ISPs to block email coming from some of the largest email service providers (ESPs) — companies that help some of the world’s biggest brands reach customers via email. On Monday, those ESPs soon began hearing from their clients who were having trouble getting their marketing emails delivered.

In two different posts published at wordtothewise.com, Spamhaus explained its reasoning for the listings, noting that a great many of the organizations operating the lists that were spammed in the attack did not bother to validate new signups by asking recipients to click a confirmation link in an email. In effect, Spamhaus reasoned, their lack of email validation caused them to behave in a spammy fashion.

“The issue is the badly-run ‘open’ lists which happily subscribed every address without any consent verification and which now continue as participants in the list-bombing of government addresses,” wrote Spamhaus CEO Steve Linford. It remains unclear whether hacked accounts at ESPs also played a role.

Also writing for wordtothewise.com, Laura Atkins likened email subscription bombs like this to “distributed denial of service” (DDoS) attacks on individuals.

“They get so much mail from different places they are unable to use their mailbox for real mail,” she wrote. “The hostile traffic can’t be blocked because the mail is coming from so many different sources.”

Atkins said over 100 addresses were added to mailing lists, many from Internet addresses outside the United States.

“The volumes I’m hearing here are significantly high that people cannot use their mailboxes. One sender identified fewer than 10 addresses each signed up to almost 10,000 of their customer lists during a 2 week period,” Atkins wrote. “Other senders have identified addresses that look to be part of the harassment campaign and are working to block mail to those addresses and get them off their lists.” Continue reading →


14
Aug 13

Buying Battles in the War on Twitter Spam

The success of social networking community Twitter has given rise to an entire shadow economy that peddles dummy Twitter accounts by the thousands, primarily to spammers, scammers and malware purveyors. But new research on identifying bogus accounts has helped Twitter to drastically deplete the stockpile of existing accounts for sale, and holds the promise of driving up costs for both vendors of these shady services and their customers.

Image: Twitterbot.info

Image: Twitterbot.info

Twitter prohibits the sale and auto-creation of accounts, and the company routinely suspends accounts created in violation of that policy. But according to researchers from George Mason University, the International Computer Science Institute and the University of California, Berkeley, Twitter traditionally has done so only after these fraudulent accounts have been used to spam and attack legitimate Twitter users.

Seeking more reliable methods of detecting auto-created accounts before they can be used for abuse, the researchers approached Twitter last year for the company’s blessing to purchase credentials from a variety of Twitter account merchants. Permission granted, the researchers spent more than $5,000 over ten months buying accounts from at least 27 different underground sellers.

In a report to be presented at the USENIX security conference in Washington, D.C. today, the research team details its experience in purchasing more than 121,000 fraudulent Twitter accounts of varying age and quality, at prices ranging from $10 to $200 per one thousand accounts.

The research team quickly discovered that nearly all fraudulent Twitter account merchants employ a range of countermeasures to evade the technical hurdles that Twitter erects to stymie the automated creation of new accounts.

“Our findings show that merchants thoroughly understand Twitter’s existing defenses against automated registration, and as a result can generate thousands of accounts with little disruption in availability or instability in pricing,” the paper reads. “We determine that merchants can provide thousands of accounts within 24 hours at a price of $0.02 – $0.10 per account.”

SPENDING MONEY TO MAKE MONEY

For example, to fulfill orders for fraudulent Twitter accounts, merchants typically pay third-party services to help solve those squiggly-letter CAPTCHA challenges. I’ve written here and here about these virtual sweatshops, which rely on low-paid workers in China, India and Eastern Europe who earn pennies per hour deciphering the puzzles.

topemailThe Twitter account sellers also must verify new accounts with unique email addresses, and they tend to rely on services that sell cheap, auto-created inboxes at HotmailYahoo and Mail.ru, the researchers found. “The failure of email confirmation as a barrier directly stems from pervasive account abuse tied to web mail providers,” the team wrote. “60 percent of the accounts were created with Hotmail, followed by yahoo.com and mail.ru.”

Bulk-created accounts at these Webmail providers are among the cheapest of the free email providers, probably because they lack additional account creation verification mechanisms required by competitors like Google, which relies on phone verification. Compare the prices at this bulk email merchant: 1,000 Yahoo accounts can be had for $10 (1 cent per account), and the same number Hotmail accounts go for $12. In contrast, it costs $200 to buy 1,000 Gmail accounts.

topcountriesFinally, the researchers discovered that Twitter account merchants very often spread their new account registrations across thousands of Internet addresses to avoid Twitter’s IP address blacklisting and throttling. They concluded that some of the larger account sellers have access to large botnets of hacked PCs that can be used as proxies during the registration process.

“Our analysis leads us to believe that account merchants either own or rent access to thousands of compromised hosts to evade IP defenses,” the researchers wrote.

Damon McCoy, an assistant professor of computer science at GMU and one of the authors of the study, said the top sources of the proxy IP addresses were computers in developing countries like India, Ukraine, Thailand, Mexico and Vietnam.  “These are countries where the price to buy installs [installations of malware that turns PCs into bots] is relatively low,” McCoy said.

Continue reading →


31
Jul 12

Dropbox: Password Breach Led to Spam

Two weeks ago, many Dropbox users began suspecting a data breach at the online file-sharing service after they started receiving spam at email addresses they’d created specifically for use at Dropbox. Today, the company confirmed that suspicion, blaming the incident on a Dropbox employee who had re-used his or her Dropbox password at another site that got hacked.

In a statement released on its blog this evening, DropBox’s Aditya Agarwal wrote:

Our investigation found that usernames and passwords recently stolen from other websites were used to sign in to a small number of Dropbox accounts. We’ve contacted these users and have helped them protect their accounts.

A stolen password was also used to access an employee Dropbox account containing a project document with user email addresses. We believe this improper access is what led to the spam. We’re sorry about this, and have put additional controls in place to help make sure it doesn’t happen again.

A Dropbox spokeswoman said the company is not ready to disclose just how many user account credentials may have been compromised by this password oops, noting that the investigation is still ongoing.

Continue reading →


17
Jul 12

Spammers Target Dropbox Users

“Always have your stuff when you need it with Dropbox.” That’s the marketing line for the online file storage service, but today users have had difficulty logging into the service. The outages came amid reports that many European Dropbox users were being blasted with spam for online casinos, suggesting some kind of leak of Dropbox user email addresses.

The trouble began earlier today, when users on the Dropbox support forums began complaining of suddenly receiving spam at email addresses they’d created specifically for use with Dropbox. Various users in Germany, the Netherlands and United Kingdom reported receiving junk email touting online gambling sites.

Dropbox did not respond to emails seeking comment, but a forum user who self-identified as a company employee said Dropbox was investigating the reports.

At around 3 p.m. ET, the company’s service went down in a rare outage, blocking users from logging into and accessing their files and displaying an error message on dropbox.com. I will update this post in the event that the company responds to my requests or provides some explanation of what caused today’s outage and the spam.

The outage and strange spam runs follow a week of high profile password and data breaches. Yahoo! acknowledged that more than 400,000 user names and passwords to Yahoo and other companies were stolen last Wednesday. Formspring, a social question-and-answer site, reset all user passwords after it discovered that approximately 420,000 password hashes from its servers had been posted to an online forum last Monday. Androidforums.com and Billabong International also disclosed password breaches last week.

Continue reading →


11
Jul 11

Spammers Sell More Non-Lifestyle Drugs in U.S.

Spam may be synonymous with male enhancement drugs, but new research shows that Americans are far more likely than buyers in other countries to turn to spam-advertised pharmacies to obtain pills to treat serious ailments–a trend that reflects differences in government health care and prescription drug policies.

Researchers at the University of California, San Diego, have collected the first data showing which drugs consumers most often buy from spam advertisements, and how much they spend at shadowy online apothecaries.

“People are going to them when they’re either too embarrassed to talk to a doctor, or when it would be far too expensive to buy these drugs otherwise,” said Chris Kanich, a PhD candidate at UCSD’s computer science department, and lead researcher of the study.

Previous estimates of monthly revenue from spam have varied dramatically, from $300,000 to more than $58 million. The UCSD researchers found that the largest rogue Internet pharmacies generate between $1 million and $2.5 million in sales each month, although they caution that their estimates are conservative.

Kanich says the figures show that although the spam-advertised market is substantial, it is not nearly as big as some have claimed, and falls short of annual expenditures on technical anti-spam solutions by corporations and ISPs.

This is an excerpt from a piece I wrote that was published today in MIT Technology Review. Read the full story here. The UCSD paper is available at this link (PDF).


1
Jul 11

Where Have All the Spambots Gone?

First, the good news: The past year has witnessed the decimation of spam volume, the arrests of several key hackers, and the high-profile takedowns of some of the Web’s most notorious botnets. The bad news? The crooks behind these huge crime machines are fighting back — devising new approaches designed to resist even the most energetic takedown efforts.

The volume of junk email flooding inboxes each day is way down from a year ago, as much as a 90 percent decrease according to some estimates. Symantec reports that spam volumes hit their high mark in July 2010, when junk email purveyors were blasting in excess of 225 billion spam messages per day. The company says daily spam volumes now hover between 25 and 50 billion missives daily. Anti-spam experts from Cisco Systems are tracking a similarly precipitous decline, from 300 billion per day in June 2010 to just 40 billion in June 2011.

Spam messages per day, July 2010 - July 2011. Image courtesy Symantec.

There may be many reasons for the drop in junk email volumes, but it would be a mistake to downplay efforts by law enforcement officials and security experts.  In the past year, authorities have taken down some of the biggest botnets and apprehended several top botmasters. Most recently, the FBI worked with dozens of ISPs to kneecap the Coreflood botnet. In April, Microsoft launched an apparently successful sneak attack against Rustock, a botnet once responsible for sending 40 percent of all junk email.

Daily spam volume July 2010 - July 2011. Image courtesy Spamcop.net

In December 2010, the FBI arrested a Russian accused of running the Mega-D botnet. In October 2010, authorities in the Netherlands arrested the alleged creator of the Bredolab botnet and dismantled huge chunks of the botnet. A month earlier, Spamit.com, one of the biggest spammer affiliate programs ever created, was shut down when its creator, Igor Gusev, was named the world’s number one spammer and went into hiding. In August 2010, researchers clobbered the Pushdo botnet, causing spam from that botnet to slow to a trickle.

But botmasters are not idly standing by while their industry is dismantled. Analysts from Kaspersky Lab this week published research on a new version of the TDSS malware (a.k.a. TDL), a sophisticated malicious code family that includes a powerful rootkit component that compromises PCs below the operating system level, making it extremely challenging to detect and remove. The latest version of TDSS — dubbed TDL-4 has already infected 4.5 million PCs; it uses a custom encryption scheme that makes it difficult for security experts to analyze traffic between hijacked PCs and botnet controllers. TDL-4 control networks also send out instructions to infected PCs using a peer-to-peer network that includes multiple failsafe mechanisms.

Continue reading →


6
Apr 11

After Epsilon: Avoiding Phishing Scams & Malware

The recent massive data leak from email services provider Epsilon means that it is likely that many consumers will be exposed to an unusually high number of email-based scams in the coming weeks and months. So this is an excellent time to point out some useful resources and tips that can help readers defend against phishing attacks and other nastygrams.

Don’t take the bait: Many people are familiar with the traditional phishing attack, which arrives in an email that appears to have been sent from your bank or ISP, warning that your account will be suspended unless you take some action immediately, usually clicking a link and “verifying” your account information, user name, password, etc. at a fake site. Commercial emails that emphasize urgency should be always considered extremely suspect, and under no circumstances should you do anything suggested in the email. Phishers count on spooking people into acting rashly because they know their scam sites have a finite lifetime; they may be shuttered at any moment (most phishing scams are hosted on hacked, legitimate Web sites). If you’re really concerned, pick up the phone (gasp!) and call the company to find out if there really is anything for you to be concerned about.

Links Lie: You’re a sucker if you take links at face value. For example, this might look like a link to Bank of America, but I assure you it is not. To get an idea of where a link goes, hover over it with your mouse and then look in the bottom left corner of the browser window. Yet, even this information often tells only part of the story, and some links can be trickier to decipher. For instance, many banks like to send links that include ridiculously long URLs which stretch far beyond the browser’s ability to show the entire thing when you hover over the link. The most important part of a link is the “root” domain. To find that, look for the first slash (/) after the “http://” part, and then work backwards through the link until you reach the second dot; the part immediately to the right is the real domain to which that link will take you.  Want to learn more cool stuff about links? Check out this guy’s site and you’ll be a link ninja in no time.

Continue reading →


11
Aug 10

Spam King Leo Kuvayev Jailed on Child Sex Charges

Undated photo of Leo Kuvayev, courtesy Spamhaus.org.

A man known as one of the world’s top purveyors of junk e-mail has been imprisoned in Russia for allegedly molesting underage girls from a Moscow orphanage, KrebsOnSecurity.com has learned.

According to multiple sources, Leonid “Leo” Aleksandorovich Kuvayev, 38, is being held in a Russian prison awaiting trial on multiple child molestation charges.

Sources in the United States and Russia said that Kuvayev, who holds dual Russian-American citizenship, was alleged to have molested more than 50 young girls he had lured away from one or more local orphanages. He was brought in for questioning after one of the girls reported the incident to Russian police, who reportedly found videotaped evidence of the incidents.

Brandon A. Montgomery, a spokesman for the Immigration and Customs Enforcement (ICE) division at the U.S. Department of Homeland Security, confirmed that Kuvayev was indicted on Aug. 3, 2009, and arrested on Sept. 15 in Moscow for child molestation charges.

“Our attaché in Moscow is working with the criminal investigative team in Russia, and the investigation is ongoing,” Montgomery said.

The Russian criminal case against Kuvayev, Case. No. 378243, charges him with violations of Russian Criminal Code 134, which prohibits “crimes against sexual inviolability and sexual freedom of the person.” According to sources in Russia familiar with the case but who asked not to be named, Kuvayev is being held in a Moscow jail awaiting trial, which is currently scheduled to start 10 months from the date of his incarceration on Dec. 22, 2009.

Kuvayev in Thailand, 2001

Kuvayev is widely considered one of the world’s most notorious spammers. Anti-spam group Spamhaus.org currently features Kuvayev as #2 on its Top 10 worst spammers list.

In 2005, the attorney general of Massachusetts successfully sued Kuvayev for violations of the CAN-SPAM Act, a law that prohibits the sending of e-mail that includes false or misleading information about the origins of the message, among other restrictions. Armed with a massive trove of spam evidence gathered largely by lawyers and security experts at Microsoft Corp., the state showed that Kuvayev’s operation, an affiliate program known as BadCow, was responsible for blasting tens of millions of junk e-mails peddling everything from pirated software to counterfeit pharmaceuticals and porn.

Continue reading →


4
Jan 10

Clever Gmail Spam Technique

The message staring out at me from my Gmail inbox said I’d received an update on my previous conversation with a sender named “vaishali”. The “(3)” next to the sender’s name suggested that I had responded to this person before, although I didn’t recognize the name. I clicked anyhow.

Alas, the message was spam for some company that I won’t mention here. As it happens, Gmail assigned the (3) to the message suggesting a threaded conversation because the sender had sent the same missive three times in a row. I have no way of knowing whether this was some clever new scheme by the spammer or merely an accident, but it certainly seems like an effective way of tricking people into clicking on an e-mail that they might normally just delete.