ASEC Weekly Phishing Email Threat Trends (November 27th, 2022 – December 3rd, 2022)

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 November 27th, 2022 to December 3rd, 2022 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. Additionally, the type that leaks login account credentials will be defined as FakePage.

Phishing Emails

During this week, the most prevalent threat type seen in phishing email attachments was Exploit, taking up 38%. A majority of them were document files with the formula editor (EQNEDT32.EXE) vulnerability.

It was then followed by fake login pages (FakePage), which took up 27%. FakePages are web pages where the threat actor has imitated the screen layout, logo, and font of the real website, leading users to enter their account and password information. The input information is sent to the threat actor’s C2 server.See <Fake Login Page C2> below

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, Downloader (7%) and Worm (2%) 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. As FakePages are web page scripts that must be executed with a web browser, they were distributed with HTML and HTM file extensions. Other malware, including Infostealer and downloader, came attached to emails with various file extensions including compressed files (ZIP, R00, RAR, LZH, etc.), IMG disk image files, and XLS document files. With the exception of fake login pages which have to be web page script files, other malware were distributed with a variety of file extensions regardless of the threat type.

Cases of Distribution

The following are distribution cases that occurred during the week from November 27th, 2022 to December 3rd, 2022. 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.

Case: Fake Login Pages (FakePage)

Email SubjectAttachment
[FedEx] Notice on Import Tax Payment Deadline – 002648974380showimage.php
Flight payment successful_ ConfirmationAir-Ticket Confirmation.html
Jimmy’s on the Mall Pty Ltd – Remittance adviceRemittance BFER.html
RATE OFFER : SHANGHAI TO MULTIPLE PORTS IN INDIA / PAPER ROLLS / 40HCShippingOrderDocs38827101HBL982022.html
Re: PAYMENT OF OUTSTANDING INVOICES/ DRAFT BL CHECKINGpaid invoice.htm
RE: [External] Wire Confirmationwire swift copy.htm
Re:Invoice balance payment of PO#CMS2018PO#6143171balance payment of pending invoice pdf.htm
Sales contract 388 and PI 388Proformer Inv 388.html
Wire & Bank ConfirmationWire Transfer.htm
Your parcel has arrived urgent pick up needed today.?DHL Air Waybill ____0392.PDF.htm
Remittance USDRemittanc Advice USD.html

Case: Malware (Infostealer, Downloader, etc.)

Email SubjectAttachment
Buenas noticiasBuenas noticias 1.doc
Kopija SWIFT-a SVRLJIG EUR 35,752.73 952PSA3223330506dvswiftsend_3011202234513_931079122.pdf.img
NEW DECEMBER ORDER PO#137810205NEW ORDER PO137810205.xls
NEW ORDER #306078910P.O #306078910.xls
NEW PRODUCT INQUIRY (Europe & Asia)Product Inquiry.xls
Payments Adjustment.payments .xls
Product Inquiry for New OrdersNew product inquiry.xls
Re: Re: Aw: Aw: Draft Shipping Docs, BL, Packing List & Commercial InvoiceDraft Of Shipping documents.xls
Re: Balanced payment for invoice 058418Bank Slip.img
Request for Quotation – RFQRFQ.xls
URGENT FIFA WORLD CUP QATAR 2022 PURCHASE ORDERQATAR 2022 PURCHASE ORDER.img
VSL: M/V COMMON CALYPSO, ORDER: NOV-A1129BMV COMMON CALYPSO.xls
Re[2]: super cool picsprv_phot.jpg.pif
Re: DHL Shipment Notification : 215158737492Awb_invoice_0000372998.lzh
Re: Draft Shipping Docs, BL, PL & Update ETASHIPMENT BL CI PL DOCUMENTS.xls
NEW DECEMBER ORDER PO#137810205NEW ORDER PO137810205.xls
DHL AWB #5401214457AWB#5401214457_Nov. 2022.zip
Re: Draft Shipping Docs, BL, PL & Update ETASHIPMENT BL CI PL DOCUMENTS.xls
RFQ_$CIF& Ex /RCI SpainRFQ_$CIF& Ex RCI Spain pdf.r00
#ERROR!Swift MT03pdf.r01
InquiryQuotation_2200001635.img
Swift Payment CopySWIFT copy.29112022.Pdf.zip
Re: Inquiry33690120220531MES_S Quote.img
Re[2]: super cool picsprv_phot.jpg.pif
Re: DHL Shipment Notification : 215158737492Awb_invoice_0000372998.lzh
Re: Draft Shipping Docs, BL, PL & Update ETASHIPMENT BL CI PL DOCUMENTS.xls
NEW DECEMBER ORDER PO#137810205NEW ORDER PO137810205.xls
DHL AWB #5401214457AWB#5401214457_Nov. 2022.zip
Re: Draft Shipping Docs, BL, PL & Update ETASHIPMENT BL CI PL DOCUMENTS.xls
RFQ_$CIF& Ex /RCI SpainRFQ_$CIF& Ex RCI Spain pdf.r00
Re: follow up: payment: November 11-28-2022Swift MT03pdf.r01
InquiryQuotation_2200001635.img
Re: Inquiry33690120220531MES_S Quote.img
RE: TT Balance For USD 28,770BNK0002334789532_USD28,770.00.lzh
Buyer-Splash; PI: O11-221101427PI O11-221101427.PDF.GZ
Re: Balanced payment for invoice 058418Bank Slip.img
DHL On Demand DeliveryDocumentos DHL-022743.xlsx
AW: Re: REMITTANCEStransaction_history_2022121-15712.gz
Payment List – 2022.12.1RefA0BL75464.xlsx
Shipping Docs B/L A01-2201139LDOCUMENTOSNOG18697208.img
Quote RequestRefTT011222.img

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: ‘Payment,’ ‘Tax’

There were multiple malicious emails that disguised themselves as having been sent from certain companies by using transaction-related keywords such as ‘payment‘ and ‘tax.’ The emails below are attached with HTML and PHP files, and both of them are phishing pages (FakePage) disguised as login pages.

Fake Login Page (FakePage) C2 URL

When users enter their IDs and passwords on the fake login page 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.

  • hxxps://www.elit.com.mx/login.php
  • hxxps://carlasbastiux.cc/YqTR09/feedback.php
  • hxxps://erfvh.gq/o/PDF-NEW.php
  • hxxps://www.agroallied.cf/upload/zender.php
  • hxxps://ralonso.com//wp-admin/cs/NEW-PDF.php
  • hxxps://submit-form.com/JeRl7xMP
  • hxxps://leptodactylous-tubs.000webhostapp.com/feed.php

Preventing Phishing Email Attacks

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 antivirus software.

According to the MITRE ATT&CK framework, phishing email attacks correspond to the following techniques.

  • Phishing for Information (Reconnaissance, ID: T1598[1])
  • Phishing (Initial Access, ID: TI1566[2])
  • Internal Spearphishing (Lateral Movement, ID: T1534[3])

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