Advisory: Malware Delivered by Email

Please beware that several individuals at UT Arlington have reported receiving email messages containing an attached “.zip” files that contains hidden malware (malicious software).

The malware appears to be a ransomware (cryptolocker variant) – it will encrypt files on the infected computer as well as network drives. The email subject line is not consistent and may have one of the following subject lines:

  • Commission
  • Please find attached invoice no: <<random number>>

Your Actions:

  • If you receive a suspicious or unexpected email similar to the description above, do not open the attachment.  Instead, we ask you to send the email as an attachment to spam@uta.edu for analysis.
  • If you are expecting legitimate email with attached zip file, you will need to manually release it from quarantine. The email system should notify you of emails being placed in quarantine, or you can login to https://quarantine.uta.edu/ to check quarantined mail.  Please do not restore and open any suspicious or unexpected attachments you may find within the quarantine.
  • If you received the message and opened the attachment, please contact OIT help desk for assistance.

To learn about Ransomware:
http://www.uta.edu/security/ransomware/

To learn about Phishing:
http://www.uta.edu/security/phishing/

Example 1 of the message:

From: document@uta.edu [mailto:document@uta.edu]
Sent: Monday, August 29, 2016 5:58 AM
To: <<recepient>>
Subject: Please find attached invoice no: 6862055379

Attached is a Print Manager form.

Format = Portable Document Format File (PDF) ________________________________

Disclaimer

This email/fax transmission is confidential and intended solely for the person or organisation to whom it is addressed. If you are not the intended recipient, you must not copy, distribute or disseminate the information, or take any action in reliance of it. Any views expressed in this message are those of the individual sender, except where the sender specifically states them to be the views of any organisation or employer. If you have received this message in error, do not open any attachment but please notify the sender (above) deleting this message from your system. For email transmissions please rely on your own virus check no responsibility is taken by the sender for any damage rising out of any bug or virus infection.

End of Example 1

Example 2 of the message:

From: <<random name and email address>>>
Sent: Monday, August 29, 2016 4:12 AM
To: <<recepient>>
Subject: Commission

Good morning <<name of recepient>>

Here is the excel file of the commission you earned last month. Please analyze the attachment to confirm the amount.

Regards,

<<Random Name>>

End of Example 2

 

Crypto-malware Ransomware Advisory Alert

Over the past few months, UT Arlington has fallen victim to Crypto-malware. In the two instances we’ve handled, documents in department K: drives were encrypted. We have recently received a notice from the Texas Department of Information Resources (DIR) Office of the CISO alerting us to several ransomware infections within the state.  The infections include variants “CryptoLocker” and “CryptoWall.”

According to DIR, the Trojan appears to have been spread mainly though emails and in one case the email was presented as a fax confirmation.  At UT Arlington, both infections involved employees browsing to websites that were infected. The computers involved had vulnerable Java and/or Adobe plug-ins; there is strong indication that this was the attack vector for the ransomware.

While it is possible to remove the virus itself, the ISO is unaware of any method to decrypt the files.  The private key, needed for decryption, is stored on a Command and Control server and is only available to the attacker. The only way to recover from a Crypto attack is to restore from backups.

We urge all departments to ensure their systems and applications are fully patched, their anti-virus is up-to-date, and ensure current backups of critical files exist in approved locations. Approved locations include OIT managed K: and J: drives, UTA CrashPlan and UTA Box.com

Be aware of the Cryptolocker malware

Please be aware that a potentially new variant of the Cryptolocker ransomware has been identified. “Ransomware” is a new category of malware that can prevent access to a computer, or the data on it, unless the victim pays a ransom to the malware creator. The Cryptolocker malware encrypts files on the victims computer and then demands payment for the files to be unlocked.

Because this is a new variant of the malware, there are no current ways to protect you from it. The only protection is to not open attachments that you are not expecting or that look suspicious.  The malware is primarily delivered via email and often contain a subject line enticing you to open an accompanying attachment. Below is an example of the message (Subject: Invoice Payment Confirmation; Attachment: Invoice_Details_01.04.2014.zip).


The malware can potentially be sent to your UTA email or your personal email (e.g. gmail, Hotmail, yahoo, etc) account.

If you fall victim to this virus, you will not be able to unlock your files and must rely on your backups. The malware can be aggressive has been known to encrypt files on local hard drives, external drives and potentially your file shares (e.g. your K: and J: drives).

UTA Employees: To backup your data on a UTA owned computer, you may use CrashPlan  (search for “CrashPlan” in the search box on the UTA website).

For updates on this advisory, please check back periodically or send an email to security@uta.edu. If you need help on how to use CrashPlan or if you are a victim of this virus, contact the Help Desk at 2-2208.

Please see our previous blog entry about Cryptolocker for background and tips.