Cisco Security has detected significant activity related to Portuguese-language spam e-mail messages that claim to contain an attached report from the United States Office of Foreign Assets Control (OFAC). The text in the e-mail message instructs the recipient to open the attachment to view the report. However, the document is a malicious .xls file that, when executed, attempts to infect the target system with malicious code.
E-mail messages that are related to this threat (RuleID2807) may contain the following file: ofac_deposit.xls
The ofac_deposit.xls file has an approximate file size of 64,512 bytes. The MD5 checksum, which is a unique identifier of the executable, is the following string: 0x326c99b68eadb98da375b5dcb7685cf7
The following text is a sample of the e-mail message that is associated with this threat outbreak:
Subject: OFAC has declined your deposit.
We hereby inform you that your transaction has been blocked by OFAC, dated 07/06/2010. If you are aware of the problem please retry the transaction as soon as possible to validate your deposit within the week.
Please view the attached report of the declined deposit by OFAC, the file is a Microsoft Excell Spreadsheet.
United States Department of the Treasury.
E-mail messages related to this threat appear to be associated with the Trojan/DocDrop-Q malware, which exploits a vulnerability in Microsoft Excel that is described in IntelliShield Alert 19322. This trojan attempts to download and execute another executable file that contains characteristics of the self-propagating Mal/Koobface-G worm.
Cisco Security analysts examine real-world e-mail traffic data that is collected from over 100,000 contributing organizations worldwide. This data helps provide a range of information about and analysis of global e-mail security threats and trends. Cisco will continue to monitor this threat and automatically adapt IronPort systems to protect customers. This report will be updated if there are significant changes or if the risk to end users increases.
Cisco IronPort Virus Outbreak Filters protect customers during the critical period between the first exploit of a virus outbreak and the release of vendor antivirus signatures. E-mail that is managed by Cisco and end users who are protected by Cisco IronPort web security appliances will not be impacted by these attacks. Cisco IronPort appliances are automatically updated to prevent both spam e-mail and hostile web URLs from being passed to the end user.
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