ASEC Weekly Phishing Email Threat Trends (June 11th, 2023 – June 17th, 2023) – ASEC BLOG

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 June 11th, 2023 to June 17th, 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 Infostealer (51%) such as AgentTesla, FormBook, and AveMaria that leaks user credentials saved in web browsers, emails, and FTP clients. The second most prevalent type was FakePage (18%), which refers to 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. It was then followed by Downloader with 7%, This type downloaded various additional malware such as Infostealers and backdoors. Aside from those mentioned above, Trojan (7%) and Exploit (3%) types were detected.

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, 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 June 11th, 2023 to June 17th, 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
(Invoice) Original BL, PL, CI_AWB#41********18	DHLSHippingDocument.pdf.html
Paid Invoice	PAID INVOICE.shtml
EFT Remittance Advice Notification for Voucher#70828- Thursday, June 15, 2023 5:51 p.m..	EFT RemittanceAdvice-susung.kim.shtml
FedEx Shipment Notification	FedEx SCANNED ORIGINAL DOC.html
RE: RE: Re: Payment	Confirmation.html
FYI: AWB_Shipment Arrival Notice Ref#Jhpark00906142023	DHL AWB SHIPMENT#Jhpark00906142023 .docx.shtml
IT3(b) Sertifikaat	IT3(b)-Certificate.pdf.html
FW:ATTACHED SWIFT COPY 6/10/2023 2:27:07 p.m.	AWDPAYMENT-RECEIPT.html
FYI: AWB_Shipment Arrival Notice Ref#*****00906142023	DHL AWB SHIPMENT#*****00906142023 .docx.shtml
JUNE P.O _3000000821	JUNE P.O _3000000821.Shtm
OCHRONA NIELETNICH	0077628.pdf
Action Required: You Have New Pending Payment	American_Express_Account_Credited_New_Payment.html
Cosmax USA PO# 9378784733	PO#9378784733.pdf.htm
Your DHL Express shipment request	Shipment-Order.html
[FedEx] Tariffs payment notice (Tax Invoice)	FedEx.html
DHL Your delivery address is wrong.	AWB #0987654347.htm
EMS Shipping电子发票已成功发行	EMS.shtml
FedEx Shipment Arrival Notification	FedEx shippingdoc.htm
Re: Fw: Payment Remittance	629-ACH-2023-0616-153214.shtml
Tax Audit Investigation Excersise As Per Finance Act 2022; Issued To ******@*****.biz	Tax Demand Notice.html
Enterprise No: K2023819613 Annual Returns Document Ref: 9388661146	COR15.1A.html
RFQ	RFQ.pdf.html
Re: New Purchase Order	New Purchase OrderI_.htm
PO 20230610 #June Shipment	Original Shipping document BL, PL, CI_.htm
– Please find Invoice-A00420427 Received 6/12/2023.	-Due inv038976-ks1010.shtm
shipping document with payment 16 Jun 2023.	dhl-shipment_invoice PI-Bill Of Lading#998454.htm
customs declaration information	FedEx .html

Keywords to Beware of: ‘FedEx’

The keyword for this week is ‘FedEx’. The threat actor impersonated a distributor to distribute a FedEx phishing email. The attached “FedEx SCANNED ORIGINAL DOC.html” executes page disguised as a Adobe PDF login page, requesting the user to enter their ID and password. As such, users are advised to take closer looks at the file names of email attachments before opening them and also check if the attachments are related to the subject of the email.

• Phishing URL: https[:]//formspree[.]io/f/myyazkbv

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[:]//sattaonmobile[.]com/new/1drv[.]php
• https[:]//dovercorrp[.]com/zong/river[.]php
• https[:]//hanbayinc[.]com/xs/omi/send[.]php
• https[:]//rsm[.]rsmsolutions[.]nl/wp-admin/zZ/port25[.]php
• https[:]//www[.]spgiutar[.]com/mmc/fdpxoGur23f[.]php
• https[:]//chat[.]junglist[.]us/css/send[.]php
• https[:]//gdmc[.]africa/X/cloudlog[.]php
• https[:]//foun-oger[.]serveblog[.]net/xmd/
• https[:]//acliftunnel[.]tk/woody/net[.]php
• https[:]//tsushi-log[.]main[.]jp/cgi/mt/lib/MT/Template/tsushi/adobe/hins[.]php
• http[:]//goodwallcovering[.]com/exee[.]php
• https[:]//y6i34kids1992[.]bond/lot/lolx[.]php
• https[:]//www[.]cordobamusicgruop[.]com/zop/fdpxoGur23f[.]php
• https[:]//submit-form[.]com/XLknrnS0
• https[:]//submit-form[.]com/rht2TZcf
• https[:]//submit-form[.]com/ghJmPlKG
• https[:]//submit-form[.]com/B9OtbySl
• https[:]//formspree[.]io/f/myyazkbv
• https[:]//formspree[.]io/f/xzbqnelj

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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Source: https://asec.ahnlab.com/en/54861/