The ASEC analysis team monitors phishing email threats with the ASEC automatic sample analysis system (RAPIT) and honeypot. This post will cover the cases of distribution of phishing emails during the week from February 12th, 2023 to February 18th, 2023 and provide statistical information on each type. Generally, phishing is cited as an attack that leaks users’ login account credentials by disguising as or impersonating an institute, company, or individual through social engineering methods. On a broader note, the act is a technical subterfuge that enables the threat actor to perform attacks such as information leaks, malware distribution, and fraud against various targets. The focus of this post will be on the fact that phishing attacks mainly occur through emails. We will also provide a detailed classification of various attack methods that are based on phishing emails. Furthermore, we will make an effort to minimize user damage by introducing new attack types that have never been found before and emails that require users’ caution, along with their keywords. The phishing emails covered in this post will only be those that have attachments. Emails that have malicious links in the body without attachments will be excluded.
During this week, the most prevalent threat type seen in phishing email attachments was FakePage, taking up 39%. FakePages are web pages where the threat actor has imitated the screen layout, logo, and font of the real login pages or advertising pages, leading users to enter their account and password information. The input information is sent to the threat actor’s C2 server or used to induce users to access other fake websites. See <FakePage C2> below It was then followed by Downloader with 28%, which includes loaders such as SmokeLoader and GuLoader. The third-in-line was Infostealer with 26%. Infostealer includes malware such as AgentTesla and FormBook, and they leak user credentials saved in web browsers, emails, and FTP clients. Aside from these, Trojan (9%), Backdoor (1%), Worm (1%), and Exploit (1%) types were detected. The threat types using phishing email attachments and their order of prevalence are similar to the order of malware distribution published weekly in the <ASEC Weekly Malware Statistics>.
File Extensions in Phishing Emails
We have identified which file extensions were used by the threats above for the distribution of email attachments. Some things to note for the phishing email attachments this week are the various compress file extensions that were used to hide malware. A total of 11 different types of extensions were used: ZIP, R00, RAR, R01, R17, GZ, DAA, XZ, Z, ACE, and LZH. As for FakePages, they were distributed with web pages scripts (HTML, HTM, SHTML) that must be executed with a web browser. Other malware, including Infostealer and downloader, came attached to emails with various file extensions including compressed files (ZIP, R00, RAR), IMG disk image files, DOCX, and PDF document files.
Cases of Distribution
The following are distribution cases that occurred during the week from February 12th, 2023 to February 18th, 2023. The cases will be classified into fake login pages and malware types, including Infostealer, Downloader, Exploit, and Backdoor. The numbers in email subjects and attachment filenames are unique IDs and may vary depending on the email recipient. Distribution cases with Korean subjects were also found. These are cases that specifically targeted Korean users instead of propagating themselves globally using the identical English subject and text.
|Scan Data from FX-1C7D2_16thFeb23||Scan Data from FX-1C7D2_16thFeb23.PDF|
|All received emails have been deferred.||***.com.html|
|IMPORTANT ANNOUNCEMENT!||NOTICE OF CHANGES.pdf|
|FWD: Re: Wire Transfer Receipt||Wire Transfer Receipt.shtml|
|Comprobante Fiscal Digital Febrero :ATT 15/02/2023 07:43:03 a. m.||adjuntos_0102_.html|
|ST0RAGE QU0TA LIMIT EXCEEDED; Retreive your (47) New Pending Messages !!! On Hold||entecene.co.kr_Verify.html|
|DHL Shipping Document/Invoice Receipt||Original_Shipping_DOC#AWB.html|
|RE: SHIPPING DOCUMENT (Purchased Contract)||FedExShipmentDoc.html|
|[Korean Air] Original Invoice Customs||Original-invoice_dhlee.htm|
|Re: Proof of payment deposited for invoices||Invoice.pdf.htm|
|[FedEx] Tax Invoice Notice (Tax Invoice)||Tax-Invoice.html|
|New Order||New Order.pdf|
|Payment has been scheduled to beneficiary on 13 Feb 2023||Swift_Copy-rina.htm|
|The new file has been received successfully.||Documents Folder.html|
|DHL Shipment Notification AWB No:: 48******16 Custom Form E||Confirm Parcel AWB NO.48157-8578916.html|
|Re: Re: Quotation Request?||Quotation Request.pdf|
|Re: Re: Outstanding Invoices for processing||outstandingPayment.INV.Shtml|
|Msa INQUIRY 21019612 dated 10-02-2023 – Reminder||RFQV21019612.xls.shtml|
|INV+PYMNT+PO 546890||INV+PYMENT+PO 9878 .HTML|
|[DHL Express] Guide on Submitting Import Clearance Info – AWB # – 394475043173||DHL_Korea_AWB#394475043173.html|
|FedEx Notice on Import Tax Payment Deadline||FedEx-kskim.htm|
|AW: Fw: Payment Transfer Receipt #3142563||Payment copy.shtml|
|INVOICE,PACKING LIST & BILL OF LADEN||INVOICE & PACKING LIST.html|
|: New Shipment||Confirm Shipment.htm|
|All received emails have been deferred.||hyundairb.com.html|
|PURCHASE ORDER & INVOICE-8750||DOC -47059(2_15_2023 4_09_16 a.m.) Mixed Container.html|
|FW: Inv_0220238_from_WSFS LLC||computer.PDF.shtml|
|Payment Advice for electronic wlre transfer – Ref: HSBC03481993/081639234||Payment_adv.html|
|Re:Urgent payment order||Payment#adv.html|
|PCH-Ref-708U97SYY8||Publishers Clearing House-2023.pdf|
Case: Malware (Infostealer, Downloader, etc.)
|RE: RFQ – INQ-DOCCIA GRP||ORDER – DOCCIA #00071533.pdf(83KB).jar|
|Re Enquiry||UPDATED ORDER.docx|
|Request for Quotation||ENQUIRY.IMG|
|FW: Request for Quotation||ENQUIRY.IMG|
|#Inquiry : 201820552||Inquiry201820552.js|
|RE: FW: RE: RE: Material productions/ Worksheet||MPSNTQWR90002023.IMG|
|FW: AUTHORIZATION LETTER||whatsapp20231302.gz|
|RE: Urgent – Payment Overdue SOA||SOA.gz|
|RFQ Order No 43456767||RFQ_Order No 43456767.zip|
|DHL Shipment For Februray Notification : 45348693||Original Shipping Documents.docx|
|YOUR EMPLOYMENT STATUS FOR REDUNDANT LEAVE||SALARY RECEIPT.rar|
|SPARE PARTS PROVISION||SPARE PARTS.docx|
|New Scanned document from Nedec Office Printer||Scan_Copy264293.docx|
|Norcity Order||Norcity Sales order.docx|
|RE: Payment.||Invoice copy.gz|
|PO-#2080M 2023||Contract PO#2080.docx|
|RFQ:N20JLG| Invitation to quote for the supply||LORAN #N20JLG.docx|
|Zhangjiagang Ocean Favor_ Urgent Quotation||RFQ.IMG|
|Reservation For Room||Details for booking.docx|
|RE: ORDER||Siemens Company Profile.img|
|New:SHEKOU // INV. 2230887||Commercial Invoice No. 2230887.pdf.z|
|Payment Copy||payment slip.zip|
|Payment is completed||TT SLIP.zip|
|RE: NEW SHIPPING DRAFT COPY||DRAFT COPY.zip|
|PO #2302036 (kerisome)||Purchase Order 2302036.r01|
|SHIPPING DOC (CI,COO,PL,BL)||SHIPPING DOCUMENT.zip|
|Re: Payment INV088002904SINO||Swift Copy.rar|
|Re: Re: Re: Re: Re: Re: New order||new order list.0435527.PDF.zip|
|RE: NEW FIRM AIR DAP RATE INQUIRY FOR CNEE||DOCUMENT.zip|
|APA Contract :RFQ 2023||APA RFQ 2023.pdf.z|
|RE: RE: SOA_freight options202105-USD122986||202105-USD122986.zip|
|funds for all inv. settled||SKM20230216_$55580.88USD.ace|
|RE: CL/140/2023//: Customs Clearance BL_CI #SHIPPING – ATTENTION||BL_CL-2838374_3494432_Docx.XZ|
|Ref. IGA/PO/17493||Ref. IGAPO17493.r00|
|MV INLACO ACCORD / ETA: 20TH FEB ++ AGENT NOMINATION||DISCHG.IMG|
|AQMM General Trading LLC. LOI||AQMM General Trading LLC LOI PDF1000.r00|
|Draft Copy Cont02983||Draft_Copy_Cont02983.rar|
|Re: New Order Quotation – 0070086 – 23/16/02||Order Specifications.zip|
|PO#BO514 FEB/ 2023||PO #BO514.z|
|Status of Payment Receipt||13022023MT103.zip|
|Confirmation & Draft Documents||DRAFT INVOICE.GZ|
|Petek Debit Note LW-83322.||DEBIT NOTE.LZH|
|LEGAL ACTION / LONG OVERDUE INVOICE||DETAILS AND INVOICES.daa|
|RE: DDP AIR IMPORT FROM LHR-AMD||A.GBIN.23.00105.zip|
|Re: very nice images private||fuck_action.pif|
|BBVA-Confirming Facturas Pagadas al Vencimiento||ConfirmingPagadas.rar|
|RE: PO: 879204/1 FCR Draft 1 EFCR YAX1905070||E-FCR Docs_pdf.gz|
|PROCESSIING CONTRCT SY2-WT2103-23.||PS#049847646-4094876478MBN.001|
|RE: RE: Updated SOA 210827//: Statement 210826||STATEMETNT OF ACCOUNT.rar|
|MONEY REQUIRE||Purchase Order-pdf.gz|
|Re: Draft Docs Confirmation against PI#CK2023M1903||DRAFT DOCS INVCK2023M1903 BL PL.xls|
|Re: SOA Detail Payment for shipment invoices from Nov 11th – Jan 12||STATEMENT OF ACCOUNT CERIE 10134 Payment Advise.xls|
|By E-Mail send: Delotser Transport Operator – 0085437719||0085437719.IMG|
|RFQ-20000 TO 500000 MT/BARELLS TEST by SGS||RFQ-20000 TO 500000 MTBARELLS TEST by SGSPDF.r00|
|FW: Technical Clarification No: 1||TC 1 AHTSA 1093 1094 RO.xlsm|
|VSL: M/V COMMON CALYPSO, ORDER: JAN-A2623B||MV COMMON CALYPSO.xls|
|Re:invoice and PL 26/01/2023||invoice and PL 26012023.zip|
|Prompt Response||DoubleClick to DOWNLOAD.one|
|ETSO Kodu hk.||ETSO_ Kodunuz40Z000004399566L..exe.xz|
|Re: [Reject]RV: OFERTA PO# 000938882 NSS||ApplicationReject_68390(Jan31).one|
|PR.4828321- Request for Quotation | ATI HANDELS GmbH||RFQ #4828321.doc|
|RE: Capital Tenders Group LTD PRICE REQUEST||Capital Tenders Group LTD PRICE REQUEST DOC.r11|
|Nueva lista de pedidos y productos solicitados||#Nueva lista de pedidos y productos solicitados.pdf.img|
|FOB Shenzhen price for its MOQ||FOB Shenzhen price for its MOQ.r02|
|FW: Invoice & Signed Contract -NEW ORDER-038408||Invoice & Signed Contract 20230201.gz|
|FW: PO7574||New Order PO039445.Pdf.exe|
|ENEL ITALIA SpA_RFQ12345HG7$$||RFQ12345HG7Solar&Wind Procurement.r00|
The ASEC analysis team has selected keywords that users must look out for, based on the distribution cases above. If these keywords are included in the subject of the email, or if the same characteristics are found, users must exercise strict caution as they may be phishing emails from threat actors.
Keywords to Beware of: ‘Delivery Notice’
The keywords for this week are ‘Delivery Notice’. The threat actor from last week distributed phishing emails with subjects containing “DHL Delivery Notice”. The sender of this phishing email used the email address of Korean Air. The typos and poor grammar of the text allow us to assume that it has been translated to Korean with machine translation. Inside the email is an attachment named “_Receipt_Pdf.gz”, and when this file decompressed, there is an EXE file with a name composed of random characters. This EXE file is an Inostealer. Users should practice caution when opening attachments in emails by checking for any strange extensions and poorly written Korean.
FakePage C2 URL
When users enter their IDs and passwords on the login pages among the FakePages created by the threat actor, their information is sent to the attacker’s server. The list below shows the threat actor’s C2 addresses of fake login pages distributed during the week.
Attacks using phishing emails are disguised with content that can easily deceive users, such as invoices and tax payments, to induce users to access fake login pages or execute malware. Fake login pages are evolving by the second to closely resemble the original pages. The attackers pack malware in compressed file formats to escape the attachment scans of users’ security products. Users must practice strict caution and refer to recent cases of distribution to avoid being exposed to infection by malicious phishing emails. The ASEC analysis team recommends users follow the email security guidelines below.
- Do not execute links and attachments in emails from unverified senders until they are proven to be credible.
- Do not enter sensitive information such as login account credentials until the site is found to be reliable.
- Do not execute attachments with unfamiliar file extensions until they are found to be reliable.
- Use security products such as antimalware software.
According to the MITRE ATT&CK framework, phishing email attacks correspond to the following techniques.
- Phishing for Information (Reconnaissance, ID: T1598)
- Phishing (Initial Access, ID: TI1566)
- Internal Spearphishing (Lateral Movement, ID:T1534)
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The post ASEC Weekly Phishing Email Threat Trends (February 12th, 2023 – February 18th, 2023) appeared first on ASEC BLOG.
Article Link: https://asec.ahnlab.com/en/48390/