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Phishing: Spearphishing Link

ID Name
T1566.001 Spearphishing Attachment
T1566.002 Spearphishing Link
T1566.003 Spearphishing via Service

Adversaries may send spearphishing emails with a malicious link in an attempt to gain access to victim systems. Spearphishing with a link is a specific variant of spearphishing. It is different from other forms of spearphishing in that it employs the use of links to download malware contained in email, instead of attaching malicious files to the email itself, to avoid defenses that may inspect email attachments. Spearphishing may also involve social engineering techniques, such as posing as a trusted source.

All forms of spearphishing are electronically delivered social engineering targeted at a specific individual, company, or industry. In this case, the malicious emails contain links. Generally, the links will be accompanied by social engineering text and require the user to actively click or copy and paste a URL into a browser, leveraging User Execution. The visited website may compromise the web browser using an exploit, or the user will be prompted to download applications, documents, zip files, or even executables depending on the pretext for the email in the first place. Adversaries may also include links that are intended to interact directly with an email reader, including embedded images intended to exploit the end system directly or verify the receipt of an email (i.e. web bugs/web beacons).

Adversaries may also utilize links to perform consent phishing, typically with OAuth 2.0 request URLs that when accepted by the user provide permissions/access for malicious applications, allowing adversaries to Steal Application Access Tokens.[1] These stolen access tokens allow the adversary to perform various actions on behalf of the user via API calls. [2]

ID: T1566.002
Sub-technique of:  T1566
ⓘ
Tactic: Initial Access
ⓘ
Platforms: Google Workspace, Linux, Office 365, SaaS, Windows, macOS
ⓘ
CAPEC ID: CAPEC-163
Contributors: Jeff Sakowicz, Microsoft Identity Developer Platform Services (IDPM Services); Kobi Haimovich, CardinalOps; Mark Wee; Philip Winther; Saisha Agrawal, Microsoft Threat Intelligent Center (MSTIC); Shailesh Tiwary (Indian Army)
Version: 2.2
Created: 02 March 2020
Last Modified: 19 April 2022

Procedure Examples

ID Name Description
S0677 AADInternals

AADInternals can send "consent phishing" emails containing malicious links designed to steal users’ access tokens.[3]
S0584 AppleJeus

AppleJeus has been distributed via spearphishing link.[4]
G0006 APT1

APT1 has sent spearphishing emails containing hyperlinks to malicious files.[5]
G0007 APT28

APT28 sent spearphishing emails which used a URL-shortener service to masquerade as a legitimate service and to redirect targets to credential harvesting sites.[6][7][8][9]
G0016 APT29

APT29 has used spearphishing with a link to trick victims into clicking on a link to a zip file containing malicious files.[10][11][12]
G0022 APT3

APT3 has sent spearphishing emails containing malicious links.[13]
G0050 APT32

APT32 has sent spearphishing emails containing malicious links.[14][15][16][17][18]
G0064 APT33

APT33 has sent spearphishing emails containing links to .hta files.[19][20]
G0087 APT39

APT39 leveraged spearphishing emails with malicious links to initially compromise victims.[21][22]
S0534 Bazar

Bazar has been spread via emails with embedded malicious links.[23][24][25]
G0098 BlackTech

BlackTech has used spearphishing e-mails with links to cloud services to deliver malware.[26]
G0080 Cobalt Group

Cobalt Group has sent emails with URLs pointing to malicious documents.[27][28]
G0142 Confucius

Confucius has sent malicious links to victims through email campaigns.[29]
G0066 Elderwood

Elderwood has delivered zero-day exploits and malware to victims via targeted emails containing a link to malicious content hosted on an uncommon Web server.[30][31]
S0367 Emotet

Emotet has been delivered by phishing emails containing links. [32][33][34][35][36][37][38][38][39]
G0120 Evilnum

Evilnum has sent spearphishing emails containing a link to a zip file hosted on Google Drive.[40]
G0085 FIN4

FIN4 has used spearphishing emails (often sent from compromised accounts) containing malicious links.[41][42]
G0046 FIN7

FIN7 has conducted broad phishing campaigns using malicious links.[43]
G0061 FIN8

FIN8 has distributed targeted emails containing links to malicious documents with embedded macros.[44]
S0531 Grandoreiro

Grandoreiro has been spread via malicious links embedded in e-mails.[45][46]
S0561 GuLoader

GuLoader has been spread in phishing campaigns using malicious web links.[47]
S0499 Hancitor

Hancitor has been delivered via phishing emails which contained malicious links.[48]
S0528 Javali

Javali has been delivered via malicious links embedded in e-mails.[49]
S0585 Kerrdown

Kerrdown has been distributed via e-mails containing a malicious link.[18]
G0094 Kimsuky

Kimsuky has sent spearphishing emails containing a link to a document that contained malicious macros or took the victim to an actor-controlled domain.[50][51][52]
S0669 KOCTOPUS

KOCTOPUS has been distributed as a malicious link within an email.[53]
G0032 Lazarus Group

Lazarus Group has sent malicious links to victims via email.[54][55][56]
G0140 LazyScripter

LazyScripter has used spam emails that contain a link that redirects the victim to download a malicious document.[53]
G0065 Leviathan

Leviathan has sent spearphishing emails with links, often using a fraudulent lookalike domain and stolen branding.[57][58]
G0095 Machete

Machete has sent phishing emails that contain a link to an external server with ZIP and RAR archives.[59][60]
G0059 Magic Hound

Magic Hound has sent malicious URL links through email to victims. In some cases the URLs were shortened or linked to Word documents with malicious macros that executed PowerShells scripts to download Pupy.[61][62][63]
S0530 Melcoz

Melcoz has been spread through malicious links embedded in e-mails.[49]
G0103 Mofang

Mofang delivered spearphishing emails with malicious links included.[64]
G0021 Molerats

Molerats has sent phishing emails with malicious links included.[65]
G0069 MuddyWater

MuddyWater has sent targeted spearphishing e-mails with malicious links.[66][67]
G0129 Mustang Panda

Mustang Panda has delivered web bugs and malicious links to their intended targets.[68][69]
S0198 NETWIRE

NETWIRE has been spread via e-mail campaigns utilizing malicious links.[47]
G0014 Night Dragon

Night Dragon sent spearphishing emails containing links to compromised websites where malware was downloaded.[70]
G0049 OilRig

OilRig has sent spearphising emails with malicious links to potential victims.[71]
G0040 Patchwork

Patchwork has used spearphishing with links to deliver files with exploits to initial victims. The group has also used embedded image tags (known as web bugs) with unique, per-recipient tracking links in their emails for the purpose of identifying which recipients opened messages.[72][73][74][75]
S0453 Pony

Pony has been delivered via spearphishing emails which contained malicious links.[76]

S0650 QakBot

QakBot has spread through emails with malicious links.[77][78][79][80][81][82]
G0034 Sandworm Team

Sandworm Team has crafted phishing emails containing malicious hyperlinks.[83]
G0121 Sidewinder

Sidewinder has sent e-mails with malicious links often crafted for specific targets.[84][85]
S0646 SpicyOmelette

SpicyOmelette has been distributed via emails containing a malicious link that appears to be a PDF document.[28]
G0092 TA505

TA505 has sent spearphishing emails containing malicious links.[86][87][88][89]
G0134 Transparent Tribe

Transparent Tribe has embedded links to malicious downloads in e-mails.[90][91]
S0266 TrickBot

TrickBot has been delivered via malicious links in phishing e-mails.[92]
G0010 Turla

Turla attempted to trick targets into clicking on a link featuring a seemingly legitimate domain from Adobe.com to download their malware and gain initial access.[93]
S0476 Valak

Valak has been delivered via malicious links in e-mail.[94]
G0112 Windshift

Windshift has sent spearphishing emails with links to harvest credentials and deliver malware.[95]
G0102 Wizard Spider

Wizard Spider has sent phishing emails containing a link to an actor-controlled Google Drive document or other free online file hosting services.[96][97]
G0128 ZIRCONIUM

ZIRCONIUM has used malicious links and web beacons in e-mails for malware download and to track hits to attacker-controlled URL's.[98][99][100]

Mitigations

ID Mitigation Description
M1047 Audit

Audit applications and their permissions to ensure access to data and resources are limited based upon necessity and principle of least privilege.
M1021 Restrict Web-Based Content

Determine if certain websites that can be used for spearphishing are necessary for business operations and consider blocking access if activity cannot be monitored well or if it poses a significant risk.
M1054 Software Configuration

Use anti-spoofing and email authentication mechanisms to filter messages based on validity checks of the sender domain (using SPF) and integrity of messages (using DKIM). Enabling these mechanisms within an organization (through policies such as DMARC) may enable recipients (intra-org and cross domain) to perform similar message filtering and validation.[101][102]
M1018 User Account Management

Azure AD Administrators apply limitations upon the ability for users to grant consent to unfamiliar or unverified third-party applications.

M1017 User Training

Users can be trained to identify social engineering techniques and spearphishing emails with malicious links which includes phishing for consent with OAuth 2.0

Detection

ID Data Source Data Component
DS0015 Application Log Application Log Content
DS0029 Network Traffic Network Traffic Content
Network Traffic Flow

URL inspection within email (including expanding shortened links) can help detect links leading to known malicious sites as well as links redirecting to adversary infrastructure based by upon suspicious OAuth patterns with unusual TLDs.[2]. Detonation chambers can be used to detect these links and either automatically go to these sites to determine if they're potentially malicious, or wait and capture the content if a user visits the link.

Filtering based on DKIM+SPF or header analysis can help detect when the email sender is spoofed.[101][102]

Because this technique usually involves user interaction on the endpoint, many of the possible detections take place once User Execution occurs.

References

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