AhnLab Security Emergency response Center (ASEC) 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 May 7th, 2023 to May 13th, 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 with 72%. 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 The second in line were InfoStealers like AgentTesla and FormBook that leaks user credentials saved in web browsers, emails, and FTP clients (16%). Aside from these, Trojan (8%), Downloader (1%), Backdoor (1%), and Worm (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. FakePages were distributed with web pages scripts (HTM, HTML) that must be executed with a web browser. Other malware, including Infostealer and downloader, came attached to emails with file extensions including compressed files (RAR, Z, GZ, 7Z, etc.).
Cases of Distribution
The following are distribution cases that occurred during the week from May 7th, 2023 to May 13th, 2023. The cases will be classified into FakePage 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 identical English subject and texts.
|Urgent Order Form/SW-23****019, SW-***||New Order _SW-********, SW-*********_New RFQ 0302260142BE, 0302260142BF.htm|
|Product Quotation Inquiry Gun_Co., Ltd****||PO_7478889393.shtml|
|✈DHL Shipment Arrival Notice [AWB#*****378004]||AWBDHLShipment55409.html|
|Quotation Request Sent||00155320.html|
|Re: Re: RE: New Order PO#41900677||JLG-SILVER contract MV AP ASTAREA.xls.htm|
|[FedEx] Notice on Import Tax Payment Deadline –||FedXETX81865549.htm|
|FedEX: shared “Shipping Documents MSK1****97/110*****” with you.||Commercial Invoice._pdf.htm|
|FYI…. Correct the error on your records. (Invoice paid)||PAID-00241.html|
|[SEC=OFFICIAL:Sensitive File-ACCESS=Personal Data-Privacy-2]||Personal Data-Privacy-SecureMessageAtt.html|
|Re：(Scanned) Doc~Original Copy – FYI||Shipping document.html|
|Purchase Order 02823||Purchase-Order02823.htm|
|Protesto para: ************.******@***.com||Protesto-Consulta5512576.html|
|FW: confirm order||inv231pl432.shtml|
|RE: New Order NO.Z21239||Purchase Order NO.Z21239.pdf|
|REQUEST FOR QUOTATION: Invoice||REQUEST FOR QUOTATION_.html|
|New Ag Order||PURCHORD_802_44730_20230504082506733.html|
|[KR]: FedEx Invoice-108321198-XXXXX3239-230414160914935||FedEx Invoice-108321198-XXXXX3239-230414160914935.shtml|
|G AND H ENTERPRISES||doc_xls_0952023.html|
|RE: PO –||Dicta.pdf|
|Protesto para: ******.*******@***.com||Protesto-Consulta2291027.html|
|Please kindly see shipping invoices for payment with delivery||Payment_Receipt_11965140936.pdf.htm|
|Double Charge on Credit Card – Reservation||Credit Card Statement.pdf|
|New Order For May P.O #3000000821||MAY P.O #3000000821 .Shtm|
|RIMINDER entec Confirm Your Delivery Address||AWB-Ref_#310479442.HTML|
|Fwd:New Order Inquiry (Davis $ Shirtliff Co,. Ltd).||Confirm_Order_inquiry.html|
|Payroll direct deposit receipt||Account Department.html|
|Swift Copy Euro 23,458.31||Euro Swift Copy.z|
|Wienerberger d.o.o. New Order||Wienerberger_d.o.o_23052291.img|
|FW: WIRE INSTRUCTIONS P384757||Wire Instruction P85793.7z|
|RE: Surat Pesanan – RFQ||PT0012305.PDF.rar|
|FW: Bulk Units||VB-SM1248.docx|
|PURCHASE ORDER ( 231062 )||PO-231062.zip|
|RE: [EXTERNAL] RE: Confirmación del pedido||Se adjunta factura proforma.zip|
|[FGIP2 Project / ***] Request for Quotation MR-001 FGIP2 PJT Package / ****||[FGIP2 Project ***] Request for Quotation MR-001 FGIP2 PJT Package ****.rar|
|1*40GP_ ECU Urgent RFQ||QS20202310109051_ErgunMakina Ind_40GP_50CBM.xz|
|SWIFT Payment Receipt For Invoice||SWIFT Payment Receipt For Invoice.rar|
|[SPAM] RE: DEBIT NOTE||DEBIT NOTE.rar|
|50% ADVANCE CUSTOMER PAMENT TO ******.****||TT copy -company invoice for clien #090523.r01|
|New Order||43000690531TEZ_S order.z|
|PDA Remittance Receipt||PDA Remittance Receipt.rar|
|price list||44XYZ_S Quote.z|
|Proforma Invoice/ USD bank details||******** Chase.rar|
|RE: Amended Purchase Order||AMENDED PURCHASE ORDER.rar|
|Re: orden de compra||orden de compra.gz|
|RE: quote request||55FZ_S Quote.z|
|Release Order No for BL MEDUAF820164||Bill of Lading and Letter of Authority# 023.rar|
|RFQ _#CIF/ FOR Hyderabad||RFQ _#CIF FOR Hyderabad.r01|
|RFQ$$FOB_BASESRep. of KOREA||RFQ$$FOB_BASESRep. of KOREA.r00|
Keyword to Beware of: ‘Quotation’
The keyword for this week is ‘Quotation’. The threat actor impersonated Korean companies and distributed phishing emails (Quotation Request Sent, Product Quotation Inquiry) requesting for quotations. The body of the phishing emails were disguised to look like that of actually used emails. It seems that the threat actor obtained this through the affected company or leaked email accounts. A web page script (00155320.html, PO_78912290586868.shtml) file is attached to the email. This HTML file is a fake page disguised as the company’s page and a Microsoft Excel, and the information entered by the user is sent to the operator’s server. A web page script (00155320.html, Po_78912290586868.shtml) is being distributed by emails disguised like below and the information inputted by users are sent to the following threat actor servers:
Threat Actor URL (Quotation Request Sent): https[:]//bilalid[.]tk/fgh/na1[.]php
Threat Actor URL (Product Quotation Inquiry): https[:]//checkengineer[.]com/er/auth[.]php
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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