Lucian Constantin
CSO Senior Writer

Unusual file-infecting malware steals FTP credentials, researchers say

news
Jul 15, 20132 mins

About 70 percent of computers infected with this threat are in the U.S., according to antivirus firm Trend Micro

A new version of a file-infecting malware program that’s being distributed through drive-by download attacks is also capable of stealing FTP (File Transfer Protocol) credentials, according to security researchers from antivirus firm Trend Micro.

The newly discovered variant is part of the PE_EXPIRO family of file infectors that was identified in 2010, the Trend Micro researchers said Monday in a blog post. However, this version’s information theft routine is unusual for this type of malware.

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The new threat is distributed by luring users to malicious websites that host Java and PDF exploits as part of an exploit toolkit. If visitors’ browser plug-ins are not up to date, the malware will be installed on their computers.

The Java exploits are for the CVE-2012-1723 and CVE-2013-1493 remote code execution vulnerabilities that were patched by Oracle in June 2012 and March 2013 respectively.

Based on information shared by Trend Micro via email, a spike in infections with this new EXPIRO variant was recorded on July 11. “About 70 percent of total infections are within the United States,” the researchers said in the blog post.

Once the new EXPIRO variant runs on a system, it searches for .EXE files on all local, removable and networked drives, and adds its malicious code to them. In addition, it collects information about the system and its users, including Windows log-in credentials, and steals FTP credentials from a popular open-source FTP client called FileZilla.

The stolen information is stored in a file with a .DLL extension and is uploaded to the malware’s command and control servers.

“The combination of threats used is highly unusual and suggests that this attack was not an off-the-shelf attack that used readily available cybercrime tools,” the Trend Micro researchers said.

The theft of FTP credentials suggests that the attackers are either trying to compromise websites or are trying to steal information from organizations that is stored on FTP servers. However, it doesn’t appear that this threat is targeting any industry in particular, the Trend Micro researchers said via email.

Lucian Constantin

Lucian Constantin writes about information security, privacy, and data protection for CSO. Before joining CSO in 2019, Lucian was a freelance writer for VICE Motherboard, Security Boulevard, Forbes, and The New Stack. Earlier in his career, he was an information security correspondent for the IDG News Service and Information security news editor for Softpedia.

Before he became a journalist, Lucian worked as a system and network administrator. He enjoys attending security conferences and delving into interesting research papers. He lives and works in Romania.

You can reach him at lucian_constantin@foundryco.com or @lconstantin on X. For encrypted email, his PGP key's fingerprint is: 7A66 4901 5CDA 844E 8C6D 04D5 2BB4 6332 FC52 6D42

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