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 28th, 2023 to June 3rd, 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 36%. 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, FormBook, and AveMaria that leak user credentials saved in web browsers, emails, and FTP clients (27%). Aside from these, Trojan (22%), Downloader (10%), Exploit (2%), Worm (1%), Backdoor (1%), and Dropper (1%) 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 through web pages script (HTM, HTML, SHTM, and SHTML) documents 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 28th, 2023 to June 3rd, 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 subjects and texts.
|[FedEx] Tariffs payment notice (Tax Invoice)||FedEx.html|
|02-QT-000488 – Request for Price Q1-Project order specification request||PO-02-QT-000488 _**********.com.HTM|
|PO vkj production status MAY.29 T/T||po~vkj_mfj3987365367893.pdf|
|Your account already has +14777$||Your_balance_has_been_replenished_22%2C336%24-8615.pdf|
|When you get your money +16853$||You_are_now_rich_21.639%24_on_your_balance-263.pdf|
|FW: RE: Shipping Documents||Scanned Bill of Lading Doc.Pdf.htm|
|Re: RFQ – 3~PHASE ORD||PO-98802.shtml|
|Re: Balance payment confirmation cg06″||Bal_payment swift.shtml|
|You are now rich +11498$ on your balance!||26316%24_Need_to_move_you_have_24_hours-14255.pdf|
|Signed Shipping Documents For Consignee (********@*********.co.kr)||Bill Of Lading Copy.html|
|You are now rich +27244$ on your balance!||When_you_get_your_money_17%2C612%24-2703.pdf|
|Come on, quickly withdraw your +27662$! The account is not blocked yet||29%2C694%24_Need_to_move_you_have_24_hours-14275.pdf|
|Booking.com Invoice 8831882301||lnvoice-8831882301.pdf|
|Booking.com Invoice 9831249301||lnvoice-9831249301.pdf|
|Re: June/New-Order #Brazil-098484OBZ||June_New-Order #Brazil-098484OBZ.XLS.html|
|VERIFY YOUR ACCOUNT.||*********.comUPDATE.shtml|
|[DHL] Shipping Document // Arrival-Notification – ETA: 6/25 BL NO: 23*******||Shipping Document_Bill of Lading.Pdf.htm|
|Request for quotation||Quote.htm|
|【电子发票号码:30940297】您收到一张新的电子发票||SF E-Invoice 30940297.pdf.html|
|VERIFY YOUR **********.com ACCOUNT.||*********.comUPDATE.shtml|
|New Order for Po No. : 4500250395||PO2340943.html|
|<Request for Quotation> / Toyo Korea / ****** *** Electric||Order345009.html|
|invoice & Shipping Documents 29 May 2023||dhl-shipment_invoice PI-Bill Of Lading#998454.htm|
|Re：(Scanned) Doc~Original Copy – FYI||Shipping document.html|
|Shipment Notice – Confirm Shipping Documents||Scanned Copies of Packing List_ETD.Pdf.htm|
|MAY P.O _3000000821||MAY P.O _3000000821.Shtm|
|FW: BANK STATEMENTS (JAN – APR.) 2023||BANK STATEMENTS (JAN – APR.) 2023.zip .htm|
Case: Malware (Infostealer, Downloader, etc.)
|Reply: Reply: [DHL] Acceptance of Import Declaration (Payment Before Acceptance) – 1000452436||Import declaration acceptance statement-1000452436.rar|
|UPS Korea-att invoice content||att1-Doc^^ICNIR00112339^^ACC^^KR^^IBS^^BIV_FRI_ICN.z|
|Final Warning – Over Due Payment – Urgent Reminder!Final Warning – Over Due Payment – Urgent R….||Overdue.img|
|P. Order & Contract (A-4553)2||P. Order & Contract (A-4553)2.rar|
|New Order 220628001||New Order 220628001.PDF.iso|
|[Sending Finalized Text] G7+Partners FASS Meeting||[FINAL] ********* Action Statement for Resilient Global Food_ Security_trackchanged.docx|
|Pending DHL Shipment Notification REF: 02/6/2023||Shipping doc.img|
|Enquiry for Quotation – Works at Sector MZW-18 in ****** ****** Project||PO.028940.22.S-R224454676781-P0-MT_SAM.rar|
|Shipment Delivery Address *(Required) contact form||Required contact form..rar|
|Payment Receipt For T/T USD$140,378,00||Payment Receipt For TT USD$140,378,00.rar|
|Please review your July 2022 offer||PLAYGROUND PROJECT – 2022089928 – KDF.arj|
|INCOMING DELIVERY NOTIFICATION||Delivery Repor.iso|
|RE: RE: FW: 2023/7/24 order shipment||Automann- Order2#44096.docx|
|cargo booking to Maresk for Po SPL-036500 & SPL-037282||SPL-036500 & SPL-037282.pdf.z|
|Fatura ve GB Hk.||PROFORMA.LZH|
|Fw: Copia de pago||Copia de pago#8101227910.05302023.gz|
|New enquiry||Quotation Details_pdf.z|
|NEW ORDER||Purchase Order 982F23.Docx.img|
|Purchases Order // PO23100080||PO23100080.z|
|quote request||Purchase order.r20|
|RE: inquiry||30590120233540MES_S Quote.z|
|Re: Purchase Order No. 9455 & 9556||9455 & 9556.z|
|RE: quote request||10690531TEZ_S Quote.r09|
|Re: wonderful pics||great_pctrs.pif|
|Ref:103XXXXX Shipment of Original Documents.||DHL SHIPMENT NOTIFICATION_PDF.gz|
|SWIFT TRANSFER.||SWIFT TRANSFER.LZH|
|very cool pictures||sex-pic.jpg.exe|
|RE ; Advance in process – project #1021 (30% deposit)||invoice.xls|
|RE: Statement of Account||SOA.xls|
|RE: Booking Request||MSDS-112883pdf.7z|
|Re: “URGENT” PAYMENT BACK RETURNED TT (Ref 0066743)||006673-001.arj|
|Re: Request for Quotation via ShipServ DQR02/5-10-2023||QTN-DQR025-10-2023.rar|
|Payment Advice Note 81930 30.05.2023 – 4360A||PAYMENT COPY $79,000.00.zip|
|*** *** ****** New Order PO#HKPOORD002361-2362||New Order PO#HKPOORD002361-2362.zip|
|Certificates Of Analaysis||Certificates Of Analaysis.rar|
|Commercial and technical offer||Commercial and technical offer.rar|
|New enquiry.||MML-REQUEST FOR QUOTE_(IC 2114).IMG|
|Payment. (******* BANK ACCOUNT)||INVOICE_VM33020031052023.IMG|
|PAYMENT SWIFT //50% ADVANCE PAYMENT//||CCB SWIFT $40K.rar|
|Purchase Order PO-5093027b||PO-5093027b.r02|
|RE: Offer Request||RE Offer Request.rar|
|Re: order||33690120233531MES_S Quote.z|
|RE: ORDER JMG 06-01-2023||ORDER JMG.IMG|
|Request V-23-VJU-028-D/01 for the Voge Julie||V-23-VJU-028-DGFGRz9eenOICt9Y-xlxs.rar|
|Signed Authorization letter||Signed Authorization letter.rar|
|Urgent (TT draft copy)||MT103-draft.r20|
|RE: ****** SHIPPING COMPANY||MSDS-112703pdf.7z|
|About the payment||Remittance Copy#0128762534.pdf.gz|
|DHL awb – 4026735019||DHL awb – 4026735019_20230525.gz|
|DHL AWB – 5032675620||DHL AWB – COMMERCIAL INVOICE, BILL OF LADING, ETC DOC.gz|
|Fw: Due Invoice Payment||20230106.8203849061-mt103-Trf.gz|
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.
Keyword to Beware of: ‘Invoice’
The keyword for this week is ‘Invoice.’ For this week, it has been confirmed that multiple emails were distributed with a Korean title (UPS Korea-att invoice content) and disguised as a certain transport company. The email was attached with a malicious file with the SCR extension. The file is an Infostealer that steals information by running the normal process aspnet_compiler.exe and injecting AveMaria into that normal process. Users must pay attention to the content of the email to check for any unfamiliar file attachment extensions and poorly translated 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 URLs 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)
Subscribe to AhnLab’s next-generation threat intelligence platform ‘AhnLab TIP’ to check related IOC and detailed analysis information.