ASEC Weekly Phishing Email Threat Trends (May 7th, 2023 – May 13th, 2023)

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.

Phishing Emails

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.

Case: FakePage

Email Subject	Attachment
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
Confirm Document.	New-Order.2023.xls.shtml
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
หนังสือมอบอำนาจสำหรับข้อเสนอของคุณ	599345092876.xls.shtml
重要报价订单 （紧急处理)	Urgent#Quotation.html
Everlee Hargrove	Your.transaction.0.7495.Bitcoin.wpA2WrOTkyKUQ.pdf
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
Zariyah Gunn	Bitcoin.Transaction.0.7495.BTCeepvVzcWKiOzJMw7j2DMQaQjbwxYZ.pdf
Aliza Rich	Mining.transaction.0.7495.BTCF4arIc3oth93MmHFdcXu1.pdf
[KR]: FedEx Invoice-108321198-XXXXX3239-230414160914935	FedEx Invoice-108321198-XXXXX3239-230414160914935.shtml
Lyric Nelson	Bitcoin__Transfer__0.7495__BTCl0lysl.pdf
G AND H ENTERPRISES	doc_xls_0952023.html
Nancy Walter	Get__it__urgently__0.7495__BTCh0f8BQYsjjlMhS.pdf
RE: PO –	Dicta.pdf
Protesto para: ******.*******@***.com	Protesto-Consulta2291027.html
Please kindly see shipping invoices for payment with delivery	Payment_Receipt_11965140936.pdf.htm
Esme Clarke	Your_transaction_0.7495_Bitcoin_y9NVCAaRDijDj0TmglM1yK5PkfZn8TY4Sx.pdf
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

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.

• https[:]//formspree[.]io/f/xdovnyrz
• http[:]//liagestoraimobiliaria[.]com[.]br/wp-content/zzzzzZZZ/fdx[.]php
• https[:]//www[.]krabiview[.]com/wp-content/themes/twentythirteen/line/exee[.]php
• https[:]//www[.]sandandstoneconstruction[.]com/wp-includes/fddx/dhlrr[.]php
• https[:]//woodless-neutron[.]000webhostapp[.]com/[.]cmd/error/encodede[.]php
• http[:]//baltik-memorial[.]ru/wp-includes/Ex/Excel[.]php
• https[:]//cianindustries[.]com/view/pop/xlss[.]php
• https[:]//dkglobaljobs[.]com/static/js/will/exee[.]php
• https[:]//submit-form[.]com/YxyXVvWR
• https[:]//formspree[.]io/f/xwkjrjbp
• https[:]//californiaapostillenotary[.]com/wp-admin/PY/cloudlog[.]php
• https[:]//cozuretabi[.]com/wp-includes/widgets/juuusssst/justgm[.]php
• https[:]//opalcoms[.]nz/win/auth[.]php
• https[:]//submit-form[.]com/4X38L2pE
• https[:]//submit-form[.]com/UwzTXAQr
• https[:]//heraldic-governors[.]000webhostapp[.]com/dhlc[.]php
• https[:]//checkengineer[.]com/bran/auth[.]php

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^[1])

• • Phishing (Initial Access, ID: TI1566^[2])

• • Internal Spearphishing (Lateral Movement, ID: T1534^[3])

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