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Last week, McAfee’s Foundstone Incident Response team got hold of a piece of malware that was sent out during a phishing campaign. The campaign targeted several companies and institutes in the United Arab Emirates, Oman, Bahrain, and a couple of Caribbean islands.

The executable that was sent with the email was called emiratesstatement.exe and the pictogram of the executable tried to impersonate itself as a PDF.

• File: emiratestatement.exe
• Size: 3,325,952 bytes
• MD5:  0E37B6EFE5DE1CC9236017E003B1FC37

A sample, more than 3MB, is strange. Normally malware samples are less than 1MB. Analyzing the malware, we retrieved a simple XOR key to decrypt the contents of this file:

While running this malware through behavioral analysis we extracted more than 14 files from this executable:

Each of them had several roles in the process of execution and relation. The key components:

• Msnd.exe: a keylogger writing the output to a TMP file
• Image.exe: mail password recovery tool written by SecurityXploded
• Picture viewer.exe: browser password recovery tool written by SecurityXploded

The malware tries two options to install itself:

• Installing the msnd keylogger and activating the password recovery tools
• Opening the pid.PDF file. This PDF will open a PDF reader and the malware will inject itself into this process and activate the password-recovery tools.

During the malware’s installation, it disables the Windows firewall by using two simple .bat scripts containing the following code:

@netsh firewall set opmode disable
@cls
@netsh advfirewall set currentprofile state off

After gathering all the recovered passwords and writing them to output files, these files are converted to files starting with the prefix PIC- followed by the date/time and a numerical indicator:

After these files are created, an FTP session transfers the files to this FTP server:

A visual representation of the malware and the relations with the different modules:

The FTP site contained several folders with the PIC*.* files:

 Folders containing the PIC files:

By analyzing the output files, we found the targets of this campaign were situated in the United Arab Emirates, Bahrain, Oman, and a couple of Caribbean islands. The victims ranged from local government entities to companies operating in the telecom sector, IT, travel, and natural resources. The credentials the criminals acquired contained usernames and passwords for a variety of sites:

• Webmail of the victim’s institute/company
• Facebook
• Hotmail
• Internal CRM system
• News-site logins
• Travel reservation systems
• E-services for governmental institutes
• Firewall logins
• Tender site logins

Yara rule to detect the malware:

rule EmiratesStatement :
{
meta:
author = “Christiaan Beek”
date = “2013-06-30″
description = “Credentials Stealing Attack”
hash0 = “0e37b6efe5de1cc9236017e003b1fc37″
hash1 = “a28b22acf2358e6aced43a6260af9170″
hash2 = “6f506d7adfcc2288631ed2da37b0db04″
hash3 = “8aebade47dc1aa9ac4b5625acf5ade8f “

strings:
$string0 = “msn.klm”
$string1 = “wmsn.klm”
$string2 = “bms.klm”
condition:
all of them
}

To prevent these kinds of attacks:

• Users should not click on files attached to an email that are sent by unknown persons
• Block emails at the email gateway/mail server that contain an executable file
• Implement a spam filter that regularly imports up-to-date threat intelligence