Most people today are well aware of email spam, the electronic equivalent of junk mail. This unsolicited email usually advertises some sort of "product," although I use that term loosely here. Spammers send out hundreds of thousands of these junk email messages, using mailing lists obtained from various sources. Spam is generally not targeted in any way; the senders rely on the sheer volume of recipients to provide them with an income. Apparently sufficient numbers of people still will click on these spam messages—and even purchase products—to make spamming a viable business solution. Spam is generally not malicious in nature. By this I mean it generally doesn't include malware or viruses as part of its content.
Fewer people seem to be aware of phishing, which is actually considered a form of social engineering. Instead of blind email sent to hundreds of thousands of random users, phishing is usually targeted. Phishing attacks are launched via email or through malicious websites. They're intended to gain your trust by posing as someone you already know or trust. They gain this trust by using email addresses and names of people you already know, or by using the names of reputable organizations. This commonly includes credit card companies, banks, retailers or e-tailers (Walmart, Target, and Amazon.com, for example), and even shipping companies like UPS and FedEx. These email messages may request your account information to "verify your identity," or perhaps suggest that there's a problem with your account or a shipment coming to you. Phishing attacks may also be launched via instant messaging, text messaging, or phone calls, but the techniques are all similar.
Phishing attacks also leverage the names and reputations of charities or fund-raising organizations. They may take advantage of current events, disasters, or tragedies, such as these historical examples:
- Natural disasters such as hurricanes, tsunamis, or earthquakes
- Epidemics and health scares like avian flu, swine flu, and most recently Ebola
- Financial or economic concerns such as identity theft or credit card fraud
- Political concerns related to current elections or even scandals
- High-profile hacks like the release of celebrity photos, government email, or lists of user names/passwords
Phishing email or websites often employ malware, viruses, or other malicious code intended to compromise your computer and gain further information about you. Messages may be addressed to you by name, and they may appear to be from friends, coworkers, or organizations with which you actively do business. In other words, this email may appear in many ways to be legitimate.
Overview of Phishing Attacks
While the basic concept of phishing hasn't changed, the implementation and exploits have grown over time. In mid-October 2014 a new attack began to spread, utilizing common phishing techniques and deploying banking malware. The intent of the phishing email was to entice the recipient to open an attached PDF file purporting to be an "Unpaid invoic"—notice the spelling error! This should have been the first clue that this email was not legitimate.
The payload of this attack was Dyre/Dyreza banking malware, delivered using a recent Adobe vulnerability. This was not a "0-day" vulnerability, and Adobe had already updated the Acrobat Reader, but patch deployments and updates can lag. Attackers rely on this delay in patching our systems. They have the delivery mechanisms in place and waiting; when a new vulnerability is discovered, they're able to attack quickly.
There are many ways in which users could have avoided being impacted by this attack. I'll discuss these techniques later in this article.
Another form of attack has been taking place for some time now. It bears mentioning because it delivers a different type of payload known as ransomware. Instead of trying to steal or retrieve your personal information (name, bank information credentials, etc.), this malware encrypts files on an infected computer and issues a demand for payment in Bitcoins to decrypt them before a deadline. If the user declines to pay, or misses the deadline, the price increases. One police department apparently paid the ransom to recover some important files back in 2013. The latest variant on the theme of ransomware is known as CryptoLocker.
While this crippling malware could be frustrating to home users, it could have enormous impact on a company, government agency, or other large organization. The impacts of CryptoLocker are described in this excerpt from US-CERT (Alert TA13-309A):
The malware has the ability to find and encrypt files located within shared network drives, USB drives, external hard drives, network file shares and even some cloud storage drives. If one computer on a network becomes infected, mapped network drives could also become infected. CryptoLocker then connects to the attackers' command and control (C2) server to deposit the asymmetric private encryption key out of the victim's reach.
From this description, you can see that many computers may be affected from one initial infection. If this malware hit a corporate or government network and spread across network-mapped drives or file shares, the impact could be huge and costly.
Why We Keep Getting Caught
Phishing has been around for many years now, and the techniques are fairly consistent, yet people still get caught. Why? I believe there are three major factors:
- Trust. People outside the field of IT—and more specifically, IT security—tend to have more trust. If they receive an email message saying that their credit card has been compromised or they've missed payment on an invoice, they tend to believe it. If we get email addressed from someone we know, we trust that it's actually from that person.
- Fear. You may wonder why I say fear is a factor in the success of these attacks. We hear every day about the latest exposure of our credit card information. Major businesses have been hacked, and hundreds of thousands of customer records have been exposed. People generally fear that they may lose money, or that their credit may be negatively impacted. Phishing email tries to capitalize on this fear by warning that we must respond quickly.
- Lack of knowledge/awareness. Education is always the first job in information security. Security professionals have known for years that people are the weakest link in our defenses. This fact is especially important in cases like this, where a simple lack of understanding can lead to immediate compromise. Many people, even today, simply don't understand the risks involved with using the Internet and its many resources. Email and its attachments, websites, and file downloads all present risks that get ignored every single day.
With many avenues of attack, we must be prepared to protect ourselves in many ways. The most obvious method is to avoid the attack altogether. Here are several key points to consider:
- Patch everything! One of our best defenses is to ensure that our software isn't vulnerable to attack. Unfortunately, due to its reactive nature, patching a system usually takes place after the vulnerability is known. During that lag time, exploits and attacks are underway and our systems are vulnerable. We must patch our systems consistently. Windows updates can be set to download and install automatically. This may be fine for home users, but companies, businesses, and government organizations should test patches before they're deployed. But even this is just the tip of the iceberg. Countless other programs on our computers need to be tracked and maintained. Fortunately, many third-party software producers are implementing automatic updates into their products. Unfortunately, that still leaves a lot of shareware, freeware, and other miscellaneous software that needs to be tracked and maintained.
- Check your incoming email carefully. Many phishing attacks appear to come from legitimate companies, but no company should ever ask you to provide account or financial information. Many phishing messages may simply be addressed "Dear Customer," or they use your email address as your name. They may warn you to act quickly to avoid consequences.
- Beware of email attachments. While we need to check our email carefully, we may still miss one here and there. We must check file attachments even more carefully. Were you expecting a PowerPoint presentation from this person? Does your bank send statements as PDF attachments? Does Microsoft email software updates as file attachments?
- Don't provide personal, financial, or account information. Most phishing email provides a link to a website where you'll be asked to provide information. Never enter your information in this manner. Instead, contact the institution directly and investigate the email with them.
- Don't trust phone callers asking for personal information. Phone calls are frequently used to phish for information. Never provide account information, passwords, or personal or financial details to someone who has called you directly. There's no way for you to verify who this individual is, and a legitimate bank or business shouldn't ask you for this information.
- Use defensive software. By now we should all know that antivirus software is required on every computer. Many of these products also include features like spyware protection and blocking known malicious websites. Enable these features, and make sure they get updated frequently.
- Be careful what you share. Never send sensitive personal information via email or share it on social media sites. I've seen students post pictures of their student ID, which can also be used as a debit card. I've seen teens post a picture of their first credit card. ID badges, credit cards, debit cards, Social Security numbers, and other confidential information of this nature should never be shared online.
- Be careful what you download. We love to get free stuff, and the Internet is full of free software, videos, music, and pictures. Be careful what you download and where you download it. Even updated antivirus software can't protect you from everything.
- Check the website address carefully. Malicious sites may look like their legitimate counterparts, but the name may be misspelled, or it may use a different domain (for example, .net instead of .com).
Responding to Phishing Attacks or Compromises
What happens if you get hit by one of these attacks? In spite of all your efforts, you think you've been compromised. What should you do next? Take the following crucial steps immediately:
- Did you share something sensitive? If you think you've given out sensitive information about your company, report it immediately. Speak to your manager, your helpdesk staff, and possibly network administrators or security personnel. They can take steps to change passwords, or monitor the network for unusual activity.
- Did you share financial information? If you've shared financial information or believe your financial data may have been compromised, contact the affected institution immediately. They can work with you to monitor for unusual charges and activity on your account—even closing the account, if necessary.
- What about your passwords? If you revealed your password, change it immediately. Hopefully you don't use the same password on multiple accounts or systems. If you do, this is the perfect time to change all of your passwords—and make them all different.
Finally, the United States Computer Emergency Readiness Team (US-CERT) collects phishing email messages and website information to help people avoid becoming victims of phishing scams. You can report phishing to US-CERT by sending email to firstname.lastname@example.org.