mrmoor/cti-corpus-raw · Datasets at Hugging Face

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Microsoft applications add this to some documents when they are downloaded from the web.
However, MOTW can be bypassed by using container file formats.
IT security company Outflank detailed multiple options for red teamers to bypass MOTW mechanisms, and these techniques can be used by threat actors as well.
Threat actors can use container file formats such as ISO (.iso), RAR (.rar), ZIP (.zip), and IMG (.img) files to send macro-enabled documents.
When downloaded, the ISO, RAR, etc.
files will have the MOTW attribute because they were downloaded from the internet, but the document inside, such as a macro-enabled spreadsheet, will not.
When the document is extracted, the user will still have to enable macros for the malicious code to automatically execute, but the file system will not identify the document as coming from the web.
Additionally, threat actors can use container files to distribute payloads directly.
When opened, container files may contain additional content such as LNKs, DLLs, or executable (.exe) files that lead to the installation of a malicious payload.
bumblebee
Figure 2: Example attack chain using ISO attachments to deliver Bumblebee malware.
Proofpoint researchers initially hypothesized that XLL files may be increasingly favored in campaigns instead of macro-enabled documents.
XLL files are a type of dynamic link library (DLL) file for Excel and are designed to increase the functionality of the Excel application.
Proofpoint has seen a slight increase in the abuse of XLL files following Microsoft’s announcement to disable XL4 macros in 2021, however these filetypes are still used significantly less than ISO, RAR, and LNK files, as well as macro-enabled documents.
Campaign Statistics
Proofpoint has observed a significant decrease in macro-enabled documents leveraged as attachments in email-based threats.
The number of these threats dropped over two-thirds between October 2021 and June 2022.
In this same timeframe, the number of campaigns leveraging container files including ISO and RAR, and Windows Shortcut (LNK) attachments increased nearly 175%.
macro
Figure 3: Number of campaigns leveraging container files vs macro-enabled documents as email attachments.
This increase is driven in part by the increased use of ISO and LNK files in campaigns.
Cybercriminal threat actors are increasingly adopting these as initial access mechanisms, such as actors distributing Bumblebee malware.
The use of ISO files increased over 150% between October 2021 and June 2022.
More than half of the 15 tracked threat actors that used ISO files in this time began using them in campaigns after January 2022.
The most notable shift in campaign data is the emergence of LNK files; at least 10 tracked threat actors have begun using LNK files since February 2022.
The number of campaigns containing LNK files increased 1,675% since October 2021.
Proofpoint has tracked multiple cybercriminal and advanced persistent threat (APT) actors leveraging LNK files with increased frequency since October 2021.
LNK files
Figure 4: Number of campaigns leveraging LNK files.
Individual threat actor activities conducted by large cybercriminal groups have a notable impact on our data.
For example, Proofpoint has observed a downward trend of threat actors using XL4 macros in campaigns.
However, XL4 macro use spiked in March 2022.
This is likely a result of TA542, the actor delivering the Emotet malware, conducting more campaigns with higher volumes of messages than preceding months.
Typically, TA542 uses Microsoft Excel or Word documents containing VBA or XL4 macros.
Emotet activity subsequently dropped off in April and it began using additional delivery methods including Excel Add In (XLL) files and zipped LNK attachments in subsequent campaigns.
LX4
Figure 5: Number of XL4 macro-related campaigns October 2021 through June 2022.
The number of VBA macros also decreased overtime and included a small spike in March and April before dropping again in May and June 2022.
This minor increase in Spring 2022 is not attributable to a single threat actor like TA542, rather multiple actors across the threat landscape were using VBA macros in this time.
VBA Macro
Figure 6: Use of VBA macros between October 2021 and June 2022.
Proofpoint has also observed a slight increase in threat actors using HTML attachments to deliver malware.
The number of malware campaigns using HTML attachments more than doubled from October 2021 to June 2022, but the overall number remains low.
Proofpoint researchers also observed threat actors increasingly adopt HTML smuggling, a technique used to "smuggle" an encoded malicious file within a specially crafted HTML attachment or web page.
Conclusion
Threat actors across the threat landscape are pivoting away from macro-enabled documents to increasingly use different filetypes for initial access.
This change is led by the adoption of ISO and other container file formats, as well as LNK files.
Such filetypes can bypass Microsoft’s macro blocking protections, as well as facilitate the distribution of executables that can lead to follow-on malware, data reconnaissance and theft, and ransomware.
Proofpoint researchers assess with high confidence this is one of the largest email threat landscape shifts in recent history.
It is likely threat actors will continue to use container file formats to deliver malware, while relying less on macro-enabled attachments.
Above the Fold and in Your Inbox: Tracing State-Aligned Activity Targeting Journalists, Media
July 14, 2022 Crista Giering, Joshua Miller, Michael Raggi and the Proofpoint Threat Research Team
Key Takeaways
Those involved in media make for appealing targets given the unique access, information, and insights they can provide on topics of state-designated import.
Proofpoint researchers have observed APT actors since early 2021 regularly targeting and posing as journalists and media organizations to advance their state-aligned collection requirements and initiatives.
The identified campaigns have leveraged a variety of techniques from using web beacons for reconnaissance to sending malware to establish initial access into the target’s network.
The focus on media by APTs is unlikely to ever wane, making it important for journalists to protect themselves, their sources, and the integrity of their information by ensuring they have an accurate threat model and secure themselves appropriately.
Overview
Journalists and media organizations suffer from many of the same threats as everyone else.
Between threat actors wanting to steal credentials to resell or to utilize compromised hosts for brokered initial access to spread ransomware, among other threats, this sector is no stranger to the dangers of the threat landscape.
Advanced persistent threat (APT) actors, however, look to those in the field of media for different purposes; ones that could have far-reaching impacts.
Journalists and media organizations are well sought-after targets with Proofpoint researchers observing APT actors, specifically those that are state-sponsored or state-aligned, routinely masquerading as or targeting journalists and media organizations because of the unique access and information they can provide.
The media sector and those that work within it can open doors that others cannot.
A well-timed, successful attack on a journalist’s email account could provide insights into sensitive, budding stories and source identification.
A compromised account could be used to spread disinformation or pro-state propaganda, provide disinformation during times of war or pandemic, or be used to influence a politically charged atmosphere.
Most commonly, phishing attacks targeting journalists are used for espionage or to gain key insights into the inner workings of another government, company, or other area of state-designated import.
Proofpoint data since early 2021 shows a sustained effort by APT actors worldwide attempting to target or leverage journalists and media personas in a variety of campaigns, including those well-timed to sensitive political events in the United States.
Some campaigns have targeted the media for a competitive intelligence edge while others have targeted journalists immediately following their coverage painting a regime in a poor light or as a means to spread disinformation or propaganda.
For the purposes of this report, we focus on the activities of a handful of APT actors assessed to be aligned with the state interests of China, North Korea, Iran, and Turkey.
Targeting Journalists’ Work Email Accounts
As observed in Proofpoint data, targeting journalists’ work email accounts is by far the most seen locus of attack used by APT actors against this target set.
It is important to note that journalists are communicating with external, foreign, and often semi-anonymous parties to gather information.
This outreach increases the risk of phishing since journalists, often by necessity, communicate with unknown recipients more so than the average user.
Verifying or gaining access to such accounts can be an entry point for threat actors for later stage attacks on a media organization’s network or to gain access to desired information.
China
Since early 2021, the APT actor tracked by Proofpoint as TA412, known also as Zirconium based on public reporting by Microsoft about a phishing reconnaissance team within this larger APT threat actor designation, has engaged in numerous reconnaissance phishing campaigns targeting US-based journalists.
TA412, which is believed to be aligned with the Chinese state interest and to have strategic espionage objectives, has favored using malicious emails containing web beacons in these campaigns.
This is a technique consistently used by the threat actor since at least 2016, however, it was likely in use for years prior.
Web beacons, which are commonly referred to as tracking pixels, tracking beacons, and web bugs, embed a hyperlinked non-visible object within the body of an email that, when enabled, attempts to retrieve a benign image file from an actor-controlled server.
Proofpoint researchers assess these campaigns have been intended to validate targeted emails are active and to gain fundamental information about the recipients’ network environments.
Web beacons can provide the following technical artifacts to an attacker which, in turn, can serve as reconnaissance information as a threat actor plans their next stage of attack:
Externally visible IP addresses
User-Agent string
Email address
Validation that the targeted user account is active
The campaigns by TA412 and their ilk evolved over the course of months, adjusting lures to best fit the current US political environment and switching to target US-based journalists focused on different areas of interest to the Chinese government.
The campaigns which targeted journalists were part of a broader pattern of reconnaissance phishing conducted by this threat actor over many years.
2021: Between January and February 2021, Proofpoint researchers identified five campaigns by TA412 targeting US-based journalists, most notably those covering US politics and national security during events that gained international attention.
Of note a very abrupt shift in targeting of reconnaissance phishing occurred in the days immediately preceding the 6 January 2021 attack on the US Capitol Building.
Proofpoint researchers observed a focus on Washington DC and White House correspondents during this time.
The malicious emails utilized subject lines pulled from recent US news articles, such as “Jobless Benefits Run Out as Trump Resists Signing Relief Bill,” “US issues Russia threat to China,” and “Trump Call to Georgia Official Might Violate State and Federal Law.”
The message bodies duplicated text included in the news articles and the web beacon URLs included a benign PNG file with a 0x0 aspect ratio that was retrieved as part of the web beacon in the following format:
hxxp://www.actor-controlled domain[.
]com/Free/<Targeted User Email Fragment>/0103/Customer.png.
The URL structure designates an actor-controlled domain, a campaign identifier, a victim identifier, a campaign date, and the name of the benign PNG resource.
TA412
Figure 1.
Sample of a TA412 web beacon reconnaissance email.
If an email client is configured to block downloadable content, then the web beacon URL should be presented to the target with an option to download the remote content, as seen in this image.
In August 2021, after a months-long break, TA412 again turned to targeting journalists, but this time those working cybersecurity, surveillance, and privacy issues with a focus on China.

Microsoft applications add this to some documents when they are downloaded from the web.

However, MOTW can be bypassed by using container file formats.

IT security company Outflank detailed multiple options for red teamers to bypass MOTW mechanisms, and these techniques can be used by threat actors as well.

Threat actors can use container file formats such as ISO (.iso), RAR (.rar), ZIP (.zip), and IMG (.img) files to send macro-enabled documents.

When downloaded, the ISO, RAR, etc.

files will have the MOTW attribute because they were downloaded from the internet, but the document inside, such as a macro-enabled spreadsheet, will not.

When the document is extracted, the user will still have to enable macros for the malicious code to automatically execute, but the file system will not identify the document as coming from the web.

Additionally, threat actors can use container files to distribute payloads directly.

When opened, container files may contain additional content such as LNKs, DLLs, or executable (.exe) files that lead to the installation of a malicious payload.

bumblebee

Figure 2: Example attack chain using ISO attachments to deliver Bumblebee malware.

Proofpoint researchers initially hypothesized that XLL files may be increasingly favored in campaigns instead of macro-enabled documents.

XLL files are a type of dynamic link library (DLL) file for Excel and are designed to increase the functionality of the Excel application.

Proofpoint has seen a slight increase in the abuse of XLL files following Microsoft’s announcement to disable XL4 macros in 2021, however these filetypes are still used significantly less than ISO, RAR, and LNK files, as well as macro-enabled documents.

Campaign Statistics

Proofpoint has observed a significant decrease in macro-enabled documents leveraged as attachments in email-based threats.

The number of these threats dropped over two-thirds between October 2021 and June 2022.

In this same timeframe, the number of campaigns leveraging container files including ISO and RAR, and Windows Shortcut (LNK) attachments increased nearly 175%.

macro

Figure 3: Number of campaigns leveraging container files vs macro-enabled documents as email attachments.

This increase is driven in part by the increased use of ISO and LNK files in campaigns.

Cybercriminal threat actors are increasingly adopting these as initial access mechanisms, such as actors distributing Bumblebee malware.

The use of ISO files increased over 150% between October 2021 and June 2022.

More than half of the 15 tracked threat actors that used ISO files in this time began using them in campaigns after January 2022.

The most notable shift in campaign data is the emergence of LNK files; at least 10 tracked threat actors have begun using LNK files since February 2022.

The number of campaigns containing LNK files increased 1,675% since October 2021.

Proofpoint has tracked multiple cybercriminal and advanced persistent threat (APT) actors leveraging LNK files with increased frequency since October 2021.

LNK files

Figure 4: Number of campaigns leveraging LNK files.

Individual threat actor activities conducted by large cybercriminal groups have a notable impact on our data.

For example, Proofpoint has observed a downward trend of threat actors using XL4 macros in campaigns.

However, XL4 macro use spiked in March 2022.

This is likely a result of TA542, the actor delivering the Emotet malware, conducting more campaigns with higher volumes of messages than preceding months.

Typically, TA542 uses Microsoft Excel or Word documents containing VBA or XL4 macros.

Emotet activity subsequently dropped off in April and it began using additional delivery methods including Excel Add In (XLL) files and zipped LNK attachments in subsequent campaigns.

LX4

Figure 5: Number of XL4 macro-related campaigns October 2021 through June 2022.

The number of VBA macros also decreased overtime and included a small spike in March and April before dropping again in May and June 2022.

This minor increase in Spring 2022 is not attributable to a single threat actor like TA542, rather multiple actors across the threat landscape were using VBA macros in this time.

VBA Macro

Figure 6: Use of VBA macros between October 2021 and June 2022.

Proofpoint has also observed a slight increase in threat actors using HTML attachments to deliver malware.

The number of malware campaigns using HTML attachments more than doubled from October 2021 to June 2022, but the overall number remains low.

Proofpoint researchers also observed threat actors increasingly adopt HTML smuggling, a technique used to "smuggle" an encoded malicious file within a specially crafted HTML attachment or web page.

Conclusion

Threat actors across the threat landscape are pivoting away from macro-enabled documents to increasingly use different filetypes for initial access.

This change is led by the adoption of ISO and other container file formats, as well as LNK files.

Such filetypes can bypass Microsoft’s macro blocking protections, as well as facilitate the distribution of executables that can lead to follow-on malware, data reconnaissance and theft, and ransomware.

Proofpoint researchers assess with high confidence this is one of the largest email threat landscape shifts in recent history.

It is likely threat actors will continue to use container file formats to deliver malware, while relying less on macro-enabled attachments.

Above the Fold and in Your Inbox: Tracing State-Aligned Activity Targeting Journalists, Media

July 14, 2022 Crista Giering, Joshua Miller, Michael Raggi and the Proofpoint Threat Research Team

Key Takeaways

Those involved in media make for appealing targets given the unique access, information, and insights they can provide on topics of state-designated import.

Proofpoint researchers have observed APT actors since early 2021 regularly targeting and posing as journalists and media organizations to advance their state-aligned collection requirements and initiatives.

The identified campaigns have leveraged a variety of techniques from using web beacons for reconnaissance to sending malware to establish initial access into the target’s network.

The focus on media by APTs is unlikely to ever wane, making it important for journalists to protect themselves, their sources, and the integrity of their information by ensuring they have an accurate threat model and secure themselves appropriately.

Overview

Journalists and media organizations suffer from many of the same threats as everyone else.

Between threat actors wanting to steal credentials to resell or to utilize compromised hosts for brokered initial access to spread ransomware, among other threats, this sector is no stranger to the dangers of the threat landscape.

Advanced persistent threat (APT) actors, however, look to those in the field of media for different purposes; ones that could have far-reaching impacts.

Journalists and media organizations are well sought-after targets with Proofpoint researchers observing APT actors, specifically those that are state-sponsored or state-aligned, routinely masquerading as or targeting journalists and media organizations because of the unique access and information they can provide.

The media sector and those that work within it can open doors that others cannot.

A well-timed, successful attack on a journalist’s email account could provide insights into sensitive, budding stories and source identification.

A compromised account could be used to spread disinformation or pro-state propaganda, provide disinformation during times of war or pandemic, or be used to influence a politically charged atmosphere.

Most commonly, phishing attacks targeting journalists are used for espionage or to gain key insights into the inner workings of another government, company, or other area of state-designated import.

Proofpoint data since early 2021 shows a sustained effort by APT actors worldwide attempting to target or leverage journalists and media personas in a variety of campaigns, including those well-timed to sensitive political events in the United States.

Some campaigns have targeted the media for a competitive intelligence edge while others have targeted journalists immediately following their coverage painting a regime in a poor light or as a means to spread disinformation or propaganda.

For the purposes of this report, we focus on the activities of a handful of APT actors assessed to be aligned with the state interests of China, North Korea, Iran, and Turkey.

Targeting Journalists’ Work Email Accounts

As observed in Proofpoint data, targeting journalists’ work email accounts is by far the most seen locus of attack used by APT actors against this target set.

It is important to note that journalists are communicating with external, foreign, and often semi-anonymous parties to gather information.

This outreach increases the risk of phishing since journalists, often by necessity, communicate with unknown recipients more so than the average user.

Verifying or gaining access to such accounts can be an entry point for threat actors for later stage attacks on a media organization’s network or to gain access to desired information.

China

Since early 2021, the APT actor tracked by Proofpoint as TA412, known also as Zirconium based on public reporting by Microsoft about a phishing reconnaissance team within this larger APT threat actor designation, has engaged in numerous reconnaissance phishing campaigns targeting US-based journalists.

TA412, which is believed to be aligned with the Chinese state interest and to have strategic espionage objectives, has favored using malicious emails containing web beacons in these campaigns.

This is a technique consistently used by the threat actor since at least 2016, however, it was likely in use for years prior.

Web beacons, which are commonly referred to as tracking pixels, tracking beacons, and web bugs, embed a hyperlinked non-visible object within the body of an email that, when enabled, attempts to retrieve a benign image file from an actor-controlled server.

Proofpoint researchers assess these campaigns have been intended to validate targeted emails are active and to gain fundamental information about the recipients’ network environments.

Web beacons can provide the following technical artifacts to an attacker which, in turn, can serve as reconnaissance information as a threat actor plans their next stage of attack:

Externally visible IP addresses

User-Agent string

Email address

Validation that the targeted user account is active

The campaigns by TA412 and their ilk evolved over the course of months, adjusting lures to best fit the current US political environment and switching to target US-based journalists focused on different areas of interest to the Chinese government.

The campaigns which targeted journalists were part of a broader pattern of reconnaissance phishing conducted by this threat actor over many years.

2021: Between January and February 2021, Proofpoint researchers identified five campaigns by TA412 targeting US-based journalists, most notably those covering US politics and national security during events that gained international attention.

Of note a very abrupt shift in targeting of reconnaissance phishing occurred in the days immediately preceding the 6 January 2021 attack on the US Capitol Building.

Proofpoint researchers observed a focus on Washington DC and White House correspondents during this time.

The malicious emails utilized subject lines pulled from recent US news articles, such as “Jobless Benefits Run Out as Trump Resists Signing Relief Bill,” “US issues Russia threat to China,” and “Trump Call to Georgia Official Might Violate State and Federal Law.”

The message bodies duplicated text included in the news articles and the web beacon URLs included a benign PNG file with a 0x0 aspect ratio that was retrieved as part of the web beacon in the following format:

hxxp://www.actor-controlled domain[.

]com/Free/<Targeted User Email Fragment>/0103/Customer.png.

The URL structure designates an actor-controlled domain, a campaign identifier, a victim identifier, a campaign date, and the name of the benign PNG resource.

TA412

Figure 1.

Sample of a TA412 web beacon reconnaissance email.

If an email client is configured to block downloadable content, then the web beacon URL should be presented to the target with an option to download the remote content, as seen in this image.

In August 2021, after a months-long break, TA412 again turned to targeting journalists, but this time those working cybersecurity, surveillance, and privacy issues with a focus on China.