ASEC Weekly Phishing Email Threat Trends (April 2nd, 2023 – April 8th, 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 April 2nd, 2023 to April 8th, 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 47%. 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 (18%), which includes loaders such as SmokeLoader and GuLoader. It was then followed by Worm (15%) and Infostealers (10%) like AgentTesla and FormBook that leak user credentials saved in web browsers, emails, and FTP clients. Aside from those mentioned above, Trojan (5%) and Dropper (5%) 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 (HTM, HTML, 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 (ZIP, 7Z, GZ, etc.).

Cases of Distribution

The following are distribution cases that occurred during the week from April 2nd, 2023 to April 8th, 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
RE: [****] ** number 1 & 2 EDM consultation related APCFS poster announcement material NM.pdf
Access to your email will be restricted confirmation failed fi***ce@********* Update-2023.htm
RE: **** number 7 & 8 DeNOx facilities request for performance improvement estimate MI.pdf
Re: [****] FGD pipe rack *** company plumbing Inform. request for forwarding and application IR.pdf
FWD: [DHL] Notice on Import Tax Payment Deadline – (INV and AWB) Original Shipping Doc#GM53726192.pdf.htm
Na*** Cou**** uploading all keywords KTX.pdf
FW: purchase order attached PO20230403.html
[External]FW: [******] Request to review affiliate service customer event RA.pdf
User email disconnected from service ********.****@********* Update-2023.htm
FW: January 2019 Security Day content sharing UT.pdf
[External]FW: [**] Request to issue certificate of career and disciplinary action form (***) EN.pdf
RE: RE: RE: RE: ****) ** number 1 & 2 EDM consultation related surface SEM measurement photo CT.pdf
SRPI Project quotation request Specfication for SRPI Project.htm
Quotation QUO91019 Quote.html
New DHL Shipment Document Arrival Notice / Shipping Documents / Original BL, Invoice & Packing List (DHL) Original BL, PL, CI Copies.htm
FedEx Shipment 811470484778: Parcel Scheduled For Delivery Shipping Document.html
R: New offer request scan001.htm
A Recent Charge on your Card was Unsuccessful Account_Security _Message.htm
New DHL Shipment Document Arrival Notice: Shipping Documents, Original BL, Invoice & Packing List. Tracking.html
ACH Payment sent On: Monday, April 3, 2023 12:51 p.m. Swift_Payment_Confirmation.pdf.shtml
Financial Statement /acc****ing@a********* Financial Statement.shtml
【132nd Canton Fair】 b****gu@*****.**.kr.htm
New Order PO54324567.htm
PO#28124758 28124758.htm
***@********* sent you files via WeTransfer WeTransfer files_*****ne@*********
Re: ******.park You Have 1 New Shared Document Truefriend_PAYMENT_CONTRACT.pdf
ACH Payment sent On:Thursday, April 6, 2023 1:43:27 PM h***m@*********.com Voutcher.shtml
RE: IBK SWIFT PAYMENT COPY IBKPaymentSwiftApproval.html
Purchase Order PO-3242 from VP Group Limited for sjlee PO-3242.html
ACH Payment sent On:Thursday, April 6, 2023 3:20:47 PM s***m@*********.com Voutcher.shtml
Re:Re:Re: Quotation order New_Order Inquiry.Htm
Re : invoice for MARCH 2023 REVISED INVOICE.shtml
Payment Transaction Notification : Success optical PAYMENT ADVICE-US$ 168,573.htm
Your grant donation – {Mrs Jacquelline Fuller} Donation Application.docx

Case: Malware (Infostealer, Downloader, etc.)

Email Subject Attachment
Open outstanding account statement Open account statement.PDF.jar
Attachment NEW ENQUIRY-pdf.gz
Re: Re: Return invoice for Payment Return invoice.rar
Pedido Pedido040323.rar
[DHL] Acceptance of Import Declaration (Payment Before Acceptance) – 7759303436 [DHL] 7759303436.rar
Your Shipment has Arrived Tracking Number! Protected Copy Doc 099876858.rar
PO#40823-LiDe Industry Group Co Limited PO#40823.rar
Request for quotation – lpr no. 8661 RDA 8661 SEBASTIANO.rar
NEW ORDER PO # IF23029361209 PO # IF23029361209.rar
RE: COSTCO Purchase Order #180222/CT24 & #160222/CT71 COSTCO Purchase Order.rar
PURCHASE ORDER 163403 Drawings.gz
Re: Fw: Payment for Outstanding Invoice INV19384783.html
World Surfaris Remittance balance$600,000.65-pdf.gz
Product Enquiry SKM51092BY210.IMG
PO NO. 42236592 PO#NO42236592000010.pdf.ARJ
SOA MARCH 2023 SOA.xls
Request from Octopus Asia Pacific SKMB710925U10.xz
SumiP Machine equipment Inquiry SUMIP MACHINE EQUIPMENT INQURIY.rar
Re[3]: super smart pics private best_img.jpg.scr
Order List Order-List.iso
Re: Document PO4377J7P Document 54737.7z
Fwd: Re: Advanced Payment Confirmation Advanced Payment – Ref_001299384596OBR11522.gz
KCI – Statement of Account – 30th march 2023 statement for HADCO S.A.O.C.exe
Purchase Order PO GEC/PO/18667 for EHAF – KSA supply Project PDF1567256210241910840.r01
Deposit made to your account Deposit slip.exe
FW:New PO#SPL036570 + RFQ036647 New PO#SPL036570.pdf.GZ
Technical Datasheet Technical_ Datasheet.7z
Re: Price Qoutation Request RFQ 2008817838749.PDF.Z
Request for Quote Request for Quote.PDF.7z
Payment Advice – Ref: [HSBC41057723] / RFQ Priority Payment Payment Advice – Ref HSBC41057723 PDF.7Z
RE: Surat Pesanan – RFQ PT.GLOBAL.PDF.rar
Payment receipt status Payment_swift 20289820.pdf.gz
DHL AWB – Invoice & Shipping Documents DHL AWB – Invoice & Shipping Documents.gz
sales contract-876 & New-Order Executiveship PO 06042023.arj
Re:Top Urgent ORDER New Order-3790028747.img
Re[5]: super wonderful images PRIVATE best-phot.gif.scr
beautiful pictures superimg.gif.scr
Re[5]: very cool pics wildpic.gif.pif
Re[4]: super nice images don’t show great_imgs.gif.exe
very wonderful photos only for you private-pctrs.jpg.scr
Re[2]: very cool pics greataction.gif.exe
sexy photos PRIVATE privatepic.jpg.scr
super sexy pics PRIVATE my-act.jpg.scr
Re[5]: very nice pictures very important best_images.jpg.scr
Re[3]: smart photo FOR YOU ONLY prv-pic.scr
super beautiful photo PRIVATE my-images.jpg.pif
nice photos private sexpctrs.pif
very nice photo sex__phot.jpg.pif
nice pics privatephot.gif.exe
Re[2]: nice picture imortant great_images.exe
smart pictures sexscene.exe
Re: super cool pics great_act.jpg.pif
very cool picture PRIVATE the_phot.gif.scr
wonderful photo mypctrs.jpg.pif
sexy images sexpic.jpg.pif
Re[3]: beautiful photo just for you best__pctrs.gif.pif
very cool pics don’t show the-plp.gif.exe
Re[2]: smart pictures privphotos.jpg.scr
Re: smart pics prvimgs.jpg.scr
sexy pics myscene.pif
smart images sexscene.scr
Re: very cool photos FOR YOU ONLY great-img.scr
sexy pictures private sexpctrs.exe
Re: cool picture imortant prv__img.gif.scr
Re[4]: sexy images privaction.exe
Re[2]: super smart pictures fuckpctrs.jpg.scr
Re: super nice images only for you great-pic.pif
Re: very nice photo fuckphotos.gif.exe
beautiful pictures very important sexaction.exe

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: ‘PDF’   

The keyword for this week is ‘PDF.’ For this week, the phishing emails attached with PDF files had titles including power plant equipment and were disguised as event promotional materials for certain companies. Instead of average documents such as invoices and purchase orders, the emails were disguised as being related to some power stations and equipment. As for the attached PDF files, their names and content were very similar despite the difference in the distributed emails’ names. The attachment names were a combination of two alphabets. When the file is viewed, it impersonates Microsoft Azure and prompts users to open it. When users click the open button, a page for entering the ID and password appears. Attempting to log in will result in account credentials being leaked to the attacker’s phishing server, as well as the user PC being infected with downloaded Qakbot malware. You can check for more details on this ASEC blog post (

  • Phishing URL: https[:]//[.]zw/ei/ei.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.

  • http[:]//demo[.]double-eleven[.]hk/wordpress/wp-content/plugins/6f7ecdf697634e1181a754ea4ca0913f/y/mm/mmd/index/fedex/FedExpress[.]php
  • https[:]//newtrp[.]com/gbooonus/processor[.]php
  • https[:]//formspree[.]io/f/myyazkbv
  • https[:]//cranecenter[.]ru/Xx/cloudlog[.]php
  • https[:]//www[.]btdpipe1ine[.]com/oc/fdpxoGur23f[.]php
  • http[:]//www[.]znbs[.]co[.]zm/Uploads/Document/DHL/log[.]php
  • https[:]//formbold[.]com/s/91wBz
  • https[:]//chuyenphat[.]nascoexpress[.]com/wp-includes/noshaking/peeking[.]php
  • https[:]//instelator-center[.]co[.]il/isso[.]checkerz[.]php
  • http[:]//chikashikakehi[.]sakura[.]ne[.]jp/file/slot-gacor-maxwin/welcome[.]php
  • http[:]//mail[.]alicevik[.]com[.]tr//makechina/lognet1[.]php
  • https[:]//kazan-oil[.]ru/fidders/msms/vmxll[.]php
  • https[:]//jaslyimpex[.]com/catalog/44/A/Excel[.]php
  • https[:]//www[.]palazzocalo[.]com/cxHiEtx/Exc/Excell[.]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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The post ASEC Weekly Phishing Email Threat Trends (April 2nd, 2023 – April 8th, 2023) appeared first on ASEC BLOG.

Article Link: ASEC Weekly Phishing Email Threat Trends (April 2nd, 2023 – April 8th, 2023) - ASEC BLOG