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 March 19th, 2023 to March 25th, 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 59%. 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 most prevalent threat type was Downloader (23%), which includes loaders such as SmokeLoader and GuLoader. It was then followed by Worm, which took up 7%. Worm is a type of malware that has a feature to spread, where it uses various methods for spreading, with one of them being using the SMTP protocol to send emails in mass quantity. Aside from these, Infostealer (6%), Trojan (4%), and Exploit (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. FakePages were distributed through web pages script (HTML, HTM, SHTML) documents 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, R09, RAR), IMG disk image files, and PDF document files.
Cases of Distribution
The following are distribution cases that occurred during the week from March 19th, 2023 to March 25th, 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 the identical English subject and text.
|[**Bank Transaction Notice]_Outward Remittance-Domestic Funds Transfer Notice||Security Email.html|
|[FedEx] Guide on Import License||AWB#.HTML|
|FW: Quotation Request PO #1192-ID_HYU-23 (Project)||Quotation Request Scan_PO #1192-ID_HYU-23.htm|
|[DHL] Notice on Import Tax Payment Deadline – (INV and AWB) ✈||ParcelDocumentDHL.html|
|FedEx Shipment Arrival Notice||AWB#989345874598.html|
|DHL Shipment Document Arrival Notice / Shipping Documents / Original BL, Invoice & Packing List||Doc#447805.htm|
|Quotation & Sample||Quotation Sample designs.pdf|
|FedEx Shipment Arrival Notification||FedEx Shippingdocs.htm|
|NEW ORDER on 3/23/2023 9:31:33 a.m.||ORDER_LST .html|
|UPS Ship Notification, Paperwork is Attached||UPS Shipment Paperworks ********@*********.co.kr.HTM|
|*******@*********.co.kr Signed Document||e-Signed_Doc_____________*******@*********.co.kr.htm|
|New DHL Shipment Document Arrival Notice / Shipping Documents /||TruefriendStatement.HTM…|
|Original BL, Invoice & Packing List.||(DHL) Original BL, PL, CI Copies.htm|
|Your parcel has arrived urgent pick up needed today||Shipping_Doc.htm|
|FedEx Ship Paperworks for Antstudio||e-Secure_FedEx03818420230315112447.html|
|RE: INVOICE PAYMENT ADVICE $77,823.44 USD INVOICE REMITTANCE COPY||invoice payment remittance copy.htm|
|**@*********.co.kr Signed Document||e-Signed_Doc_____________**@*********.co.kr.htm|
|RE: PO.14036987,14038068 shipping documents and payment via DHL (083AB单)||payment_doc & shipment#7221HKT.htm|
|********@*********.co.kr Signed Document||e-Signed_Doc_____________********@*********.co.kr.htm|
|Re: Fw:Inquiry for 2023 New Products Prices||prices.zip|
|RE: New Invoice Order Payment||NewInvoiceOrderStatement.html|
|NEW ORDER- OC#8081013559 PO#3495-1022||New order sign invoice for payment.htm|
|There is an important encrypted corporate email you need to read||Securedoc_82396476.html|
|Shipment Booking Confirmation – BL Draft is Ready for Review||Draft Bill of Lading – SHSYD4096642.htm|
|New DHL Shipment Document Arrival Notice / Shipping Documents / Original BL, Invoice & Packing List||(DHL) Original BL, PL, CI Copies.html|
|You have received an essential encrypted company email||Securedoc_05741605.html|
|An important encrypted corporate email has been sent to you||Securedoc_28422847.html|
Case: Malware (Infostealer, Downloader, etc.)
|[DHL] Acceptance of Import Declaration (Payment Before Acceptance) – 7759303436||Tax Notification – 7759303436.z|
|Statement of Account from Partners attached||Statement of Account from Partners.rar|
|RE: NEW PRODUCT ORDER||Order Quantity.xls|
|Order Enquiry 202300221||Order Enquiry 202300221.zip|
|New Customer Order||ORDER101-PDF.tar|
|World Surfaris Remittance||balance$405,000.34-pdf.gz|
|RE: Re: [subject line info removed]||report 1219844918.one|
|Re: Confirmation transfer AGS # 22-0035||Confirmation Transfer MT103_Pdf.7z|
|Re: nice picture only for you||best__plp.jpg.exe|
|Re: Fw:Inquiry for 2023 New Products Prices||New 2023 prices list.zip|
|Re: Wire confirmation details||TT copy.xls|
|Your Transport Plan has Changed – Maersk||Transport Plan.img|
|very wonderful pics PRIVATE||super-plp.pif|
|sexy photo private||superphotos.scr|
|New PO#4501250499 P/N R505567||PO#4501250499 .xls|
|RE: Re: [subject line information removed]||list-896881.zip|
|Re: very wonderful pictures don’t show||great-img.jpg.exe|
|Re: very cool images don’t show||privact.gif.exe|
|Re: very smart images PRIVATE||wild_action.gif.exe|
|very wonderful photos don’t show||sex_pic.jpg.scr|
|FW:Payment Overdue Invoices||Swift30405830330.arj|
|wonderful picture just for you||coolplp.gif.scr|
|Re: very cool pictures only for you||great_scene.jpg.pif|
|Re: cool pics||fuck__photos.jpg.scr|
|RE: WO NO 23085//EGYTVR GROUP LTD||REVISED EGYTVR GROUP LTD.r00|
|Re: Re: Happy new year!||List_1603.one|
|Fw: Re: [subject line information removed]||Scan_247.one|
|very nice photo||the-action.gif.pif|
|Daily Statement – Payment Report||Daily Statement.xz|
|Re: sexy photos||greatphotos.exe|
|Re: very wonderful images PRIVATE||privimages.gif.pif|
|Advanced payment for invoice 060296||proof of payment 20th March.r09|
|super beautiful pictures||sex_pic.exe|
|Re: very nice pics only for you||wild-images.jpg.scr|
|Re: very wonderful picture only for you||fuck-images.exe|
|INVOICE ITALY SHIPMENT PICK UP—-771001413904||INVOICE 771001413904.xz|
|Payment Advice – Ref: [HSBC41057723] / RFQ Priority Payment / Customer Ref: [PI7800152T9]||Payment Advice – Ref [HSBC41057723]PDF.7Z|
|RE: New Order||New Order.r09|
|REMITTANCE TT COPY $23,150.00_20230320.pdf||REMITTANCE TT COPY $23,150.00_20230320.pdf.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.
Keywords to Beware of: ‘Transaction Notice’
The keywords for this week are ‘Transaction Notice’. A Korean phishing email disguised as a transaction notice from a financial institute were found to be in distribution this week. Unlike most phishing pages that are poorly made, this email was quite sophisticated in terms of its disguise. In the email was a malicious HTML file which asked for the user’s ID and password before revealing its content upon being run. When the user inputs this information, it is leaked to the threat actor’s server; thus, users should not give their account credentials.
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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