[Caution] Virus/XLS Xanpei Infecting Normal Excel Files Posted By Hansoyoung , April 13, 2022 The ASEC analysis team has recently discovered the constant distribution of malware strains that spread the infection when Excel file is opened. Besides infecting normal Excel files, they can also perform additional malicious behaviors such as acting as a downloader and performing DNS Spoofing, therefore, users need to take great caution. The common trait of the malware strains is to spread the virus through the VBA (Visual Basic for Applications) codes included in Excel files. Upon opening the infected Excel…
Guide to Prevent Execution of Excel 4.0 Macro Malware – Microsoft Office 365 Product Posted By jcleebobgatenet , January 3, 2022 Excel 4.0 macro (XLM) malware is an attack method that uses Microsoft Office Excel files, and it has been established as the new document malware flow following VBA (Visual Basic Application). Excel 4.0 macro malware uses the ‘macro sheet’ feature in Excel. Each cell in the Excel sheet is composed of a function flow that can be run. Excel 4.0 macro malware has been most actively used in the recent methods of malware distribution using MS Office files. The developer…
Distribution of Malicious Excel Files Targeting Companies Amid Black Friday Season Posted By jcleebobgatenet , November 30, 2021 Malicious Excel files are being distributed to companies amid the Black Friday season. The email confirmed today (Nov 25th) is an email reported by the attacked company in Korea. Attached to the email is an Excel file that contains an Excel 4.0 Macro (XLM) macro sheet in the form of the XLSB excel binary. It checks whether the system is a domain controller then activates additional malicious features. The filename of the attached Excel file has a format of ‘promo…
Malicious Excel File Disguised as an Invoice, Possibly Targeting Companies Posted By jcleebobgatenet , October 28, 2021 The ASEC analysis team has recently discovered a malicious Excel file disguised as an invoice. This file is being distributed as an e-mail attachment with the filename of Invoice-[number]_date.xlsb. The following is the malicious e-mail that is being distributed in Korea. Upon running the Excel file, editing is restricted, prompting users to click the image within the file (see figure below). As the macro is designated to this image, the user must click the image for the macro to be…
Excel Files Becoming More Sophisticated (Distribution of Dridex and Cobalt Strike) Posted By jcleebobgatenet , July 26, 2021 The distribution method of Dridex through Excel files has been steadily discovered since last year and was introduced on this blog. Recently, the ASEC analysis team found that the Cobalt Strike tool along with Dridex is being distributed with a similar method as before. Yet unlike previous cases, recent Excel documents that are being distributed were found to perform malicious behaviors after a certain time using the task scheduler. It is assumed that the change in the operation method was…
