T1114.001: Local Email Collection
Adversaries may target user email on local systems to collect sensitive information. Files containing email data can be acquired from a user’s local system, such as Outlook storage or cache files.
Outlook stores data locally in offline data files with an extension of .ost. Outlook 2010 and later supports .ost file sizes up to 50GB, while earlier versions of Outlook support up to 20GB.[1] IMAP accounts in Outlook 2013 (and earlier) and POP accounts use Outlook Data Files (.pst) as opposed to .ost, whereas IMAP accounts in Outlook 2016 (and later) use .ost files. Both types of Outlook data files are typically stored in `C:\Users\\Documents\Outlook Files` or `C:\Users\\AppData\Local\Microsoft\Outlook`.[2]
Security context for executives and security teams
Local Email Collection matters because email caches on Windows endpoints can contain large volumes of sensitive business content even when the mailbox itself is protected in the cloud or on a mail server. Outlook .ost and .pst files may expose executive communications, legal or financial material, personal information, incident response discussions, and operational details if an adversary gains local access to a workstation.
Executive priority
Treat this as an endpoint data-exposure and incident-readiness issue, not only an email-security issue. Leaders should ask whether high-risk Windows users store Outlook data locally, whether sensitive data at rest is encrypted, whether SOC teams can see unusual access to Outlook data files, and whether incident teams have out-of-band communications available if email confidentiality is in question. The relationship history includes multiple espionage groups, campaigns, and malware families using this behavior, which supports prioritizing it for sensitive roles and regulated data environments.
Technical view
This is a Windows collection sub-technique under Email Collection. Defensive validation should focus on access to Outlook local data files, especially .ost and .pst files typically located under C:\Users\<username>\Documents\Outlook Files and C:\Users\<username>\AppData\Local\Microsoft\Outlook. Because MITRE does not provide an official detection paragraph for this object, teams should use the related detection strategy, DET0047, as direction: detect Outlook data file access and command-line tooling patterns around those files. IR playbooks should treat suspicious access to local mail stores as potential collection of sensitive content, especially on executive, finance, legal, administrator, and incident response workstations.
Likely telemetry
- Endpoint file access telemetry for .ost and .pst files in common Outlook storage paths
- Process creation and command-line telemetry involving file discovery, copying, compression, staging, or access to Outlook data files
- Endpoint detection and response alerts or file activity events on Windows user profile directories
- Windows host inventory showing where Outlook cached mode or local Outlook data files are present
- Data-at-rest encryption status for Windows endpoints and sensitive user profiles
Detection direction
- Validate that file access monitoring covers common Outlook .ost and .pst locations under user profiles, not only mail-server or cloud-mail audit logs.
- Tune for unusual processes, scripts, remote access tools, or command-line utilities accessing Outlook data files, while accounting for legitimate Outlook, backup, indexing, eDiscovery, or migration activity.
- Prioritize detections on high-value users and systems where local mail content would materially affect legal, financial, executive, operational, or incident response confidentiality.
- Use the related DET0047 context to test visibility for Outlook data file access plus command-line tooling, but do not assume coverage exists without endpoint telemetry validation.
- Correlate local email data access with broader collection, staging, or exfiltration indicators during investigations.
Mitigation priorities
- Reduce the business need for sensitive email to persist locally where feasible, especially for high-risk roles.
- Apply encryption for sensitive information at rest as represented by M1041, including Windows endpoint storage protections where appropriate.
- Maintain secure out-of-band communications channels as represented by M1060 so incident response does not depend solely on potentially exposed email.
- Review endpoint hardening, access controls, and monitoring for user profile directories containing Outlook data files.
- Include local Outlook data stores in tabletop exercises, evidence collection plans, and compliance discussions involving sensitive data handling.
Additional notes and limits
This object is a sub-technique of T1114 Email Collection and is limited to Windows in the supplied ATT&CK fields. The relationships show use by multiple groups, a campaign, and software including Carbanak, CosmicDuke, Crimson, Pupy, Smoke Loader, Empire, Emotet, KGH_SPY, Out1, QakBot, and LunarMail; this supports broad defensive relevance but does not prove current activity in any specific environment.
MITRE provides no official detection text for this technique in the supplied fields. Detection guidance here is derived from the object description, file paths, platforms, tactics, the DET0047 relationship name, and mitigation relationships. Local validation is required to determine whether Outlook data files exist, whether telemetry captures access to them, and whether observed access is legitimate.
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Local Email Collection
Adversaries may target user email on local systems to collect sensitive information. Files containing email data can be acquired from a user’s local system, such as Outlook storage or cache files.
Outlook stores data locally in offline data files with an extension of .ost. Outlook 2010 and later supports .ost file sizes up to 50GB, while earlier versions of Outlook support up to 20GB.[1] IMAP accounts in Outlook 2013 (and earlier) and POP accounts use Outlook Data Files (.pst) as opposed to .ost, whereas IMAP accounts in Outlook 2016 (and later) use .ost files. Both types of Outlook data files are typically stored in `C:\Users\\Documents\Outlook Files` or `C:\Users\\AppData\Local\Microsoft\Outlook`.[2]
How security teams should use this page
Treat this object as behavior context, not an attribution claim. Validate the related groups, software, data sources, and mitigations against official ATT&CK relationships and your own telemetry before making control-coverage decisions.
Related techniques
This mirrors the MITRE pattern of making group, software, campaign, and technique relationships scannable. Relationship notes come from mirrored ATT&CK relationship text when available.
| Domain | ID | Name | Relationship / procedure |
|---|---|---|---|
| Enterprise | T1114 | Email Collection | This object subtechnique of Email Collection. |
Groups, software, and campaigns
G0090: WIRTE
WIRTE is a cyberespionage actor, believed to be a subgroup of the Hamas-affiliated Gaza Cybergang, that has been active since at least August 2018. WIRTE has targeted diplomatic, financial, military, legal, and technology organizations across the Middle East, North Africa, and in Europe to gather intelligence. WIRTE has remained persistently active despite the ongoing Israel-Hamas conflict and has expanded their operations to include wiper malware attacks against Israeli targets.[1][2][3][4]
G1039: RedCurl
RedCurl is a threat actor active since 2018 notable for corporate espionage targeting a variety of locations, including Ukraine, Canada and the United Kingdom, and a variety of industries, including but not limited to travel agencies, insurance companies, and banks.[1] RedCurl is allegedly a Russian-speaking threat actor.[1][2] The group’s operations typically start with spearphishing emails to gain initial access, then the group executes discovery and collection commands and scripts to find corporate data. The group concludes operations by exfiltrating files to the C2 servers.
G1041: Sea Turtle
Sea Turtle is a Türkiye-linked threat actor active since at least 2017 performing espionage and service provider compromise operations against victims in Asia, Europe, and North America. Sea Turtle is notable for targeting registrars managing ccTLDs and complex DNS-based intrusions where the threat actor compromised DNS providers to hijack DNS resolution for ultimate victims, enabling Sea Turtle to spoof log in portals and other applications for credential collection.[1][2][3][4]
G0006: APT1
G0114: Chimera
G0059: Magic Hound
Magic Hound is an Iranian-sponsored threat group that conducts long term, resource-intensive cyber espionage operations, likely on behalf of the Islamic Revolutionary Guard Corps. They have targeted European, U.S., and Middle Eastern government and military personnel, academics, journalists, and organizations such as the World Health Organization (WHO), via complex social engineering campaigns since at least 2014.[1][2][3][4][5]
G1054: MirrorFace
MirrorFace is a People's Republic of China (PRC)-aligned cyberespionage actor believed to be a subgroup under the menuPass umbrella based on targeting, tools, and infrastructure overlaps. MirrorFace has been active since at least 2019, at first exclusively targeting Japanese organizations across the media, defense, diplomatic, financial, manufacturing, and academic sectors. Subsequent MirrorFace operations included targets in Central Europe and featured use of LODEINFO, HiddenFace, and UPPERCUT malware.[1][2][3][4][5][6]
G1035: Winter Vivern
Winter Vivern is a group linked to Russian and Belorussian interests active since at least 2020 targeting various European government and NGO entities, along with sporadic targeting of Indian and US victims. The group leverages a combination of document-based phishing activity and server-side exploitation for initial access, leveraging adversary-controlled and -created infrastructure for follow-on command and control.[1][2][3][4][5]
S1142: LunarMail
LunarMail is a backdoor that has been used by Turla since at least 2020 including in a compromise of a European ministry of foreign affairs (MFA) in conjunction with LunarLoader and LunarWeb. LunarMail is designed to be deployed on workstations and can use email messages and Steganography in command and control.[1]
S0226: Smoke Loader
Smoke Loader is a malicious bot application that can be used to load other malware. Smoke Loader has been seen in the wild since at least 2011 and has included a number of different payloads. It is notorious for its use of deception and self-protection. It also comes with several plug-ins. [1] [2]
S0650: QakBot
S0192: Pupy
Pupy is an open source, cross-platform (Windows, Linux, OSX, Android) remote administration and post-exploitation tool. [1] It is written in Python and can be generated as a payload in several different ways (Windows exe, Python file, PowerShell oneliner/file, Linux elf, APK, Rubber Ducky, etc.). [1] Pupy is publicly available on GitHub. [1]
S0030: Carbanak
S0115: Crimson
Crimson is a remote access Trojan that has been used by Transparent Tribe since at least 2016.[1][2]
S0363: Empire
Empire is an open-source, cross-platform remote administration and post-exploitation framework that is publicly available on GitHub. While the tool itself is primarily written in Python, the post-exploitation agents are written in pure PowerShell for Windows and Python for Linux/macOS. Empire was one of five tools singled out by a joint report on public hacking tools being widely used by adversaries.[1][2][3]
S0526: KGH_SPY
S0050: CosmicDuke
CosmicDuke is malware that was used by APT29 from 2010 to 2015. [1]
S0594: Out1
Out1 is a remote access tool written in python and used by MuddyWater since at least 2021.[1]
S0367: Emotet
C0002: Night Dragon
Night Dragon was a cyber espionage campaign that targeted oil, energy, and petrochemical companies, along with individuals and executives in Kazakhstan, Taiwan, Greece, and the United States. The unidentified threat actors searched for information related to oil and gas field production systems, financials, and collected data from SCADA systems. Based on the observed techniques, tools, and network activities, security researchers assessed the campaign involved a threat group based in China.[1]
All related ATT&CK context
Mitigation direction
Object version and sync metadata
The fields below describe the current mirrored snapshot. When Glexia retains multiple ATT&CK source imports, you can open the table to compare the same object across releases (hashes and MITRE timestamps). For MITRE’s own release notes and roadmap, see ATT&CK resources — Updates.
Imported snapshots across ATT&CK releases(1)
| Release | Bundle imported | Object version | Modified | Status | Raw hash |
|---|---|---|---|---|---|
| 19.1 | 1.1 | Current bundle | 8f415f6ccdd9… |
Mirrored ATT&CK source object
The raw object is retained through the mirrored ATT&CK source bundle and object hash. The raw endpoint returns the exact object from the mirrored bundle when available.
External references and citations
MITRE external references are preserved separately from Glexia analysis so citations remain traceable to their original source records.
- [1]Outlook File Sizes
N. O'Bryan. (2018, May 30). Managing Outlook Cached Mode and OST File Sizes. Retrieved February 19, 2020.
Open source URL - [2]Microsoft Outlook Files
Microsoft. (n.d.). Introduction to Outlook Data Files (.pst and .ost). Retrieved February 19, 2020.
Open source URL - [3]ESET Turla Lunar toolset May 2024
Jurčacko, F. (2024, May 15). To the Moon and back(doors): Lunar landing in diplomatic missions. Retrieved June 26, 2024.
Open source URL - [4]Palo Alto Ashen Lepus DEC 2025
Unit 42. (2025, December 11). Hamas-Affiliated Ashen Lepus Targets Middle Eastern Diplomatic Entities With New AshTag Malware Suite. Retrieved April 20, 2026.
Open source URL - [5]group-ib_redcurl1
Group-IB. (2020, August). RedCurl: The Pentest You Didn’t Know About. Retrieved August 9, 2024.
Open source URL - [6]TrustedSec OOB Communications
Tyler Hudak. (2022, December 29). To OOB, or Not to OOB?: Why Out-of-Band Communications are Essential for Incident Response. Retrieved August 30, 2024.
Open source URL - [7]Talos Smoke Loader July 2018
Baker, B., Unterbrink H. (2018, July 03). Smoking Guns - Smoke Loader learned new tricks. Retrieved July 5, 2018.
Open source URL - [8]Kroll Qakbot June 2020
Sette, N. et al. (2020, June 4). Qakbot Malware Now Exfiltrating Emails for Sophisticated Thread Hijacking Attacks. Retrieved September 27, 2021.
Open source URL - [9]Trend Micro Qakbot December 2020
Trend Micro. (2020, December 17). QAKBOT: A decade-old malware still with new tricks. Retrieved November 17, 2024.
Open source URL - [10]Kaspersky QakBot September 2021
Kuzmenko, A. et al. (2021, September 2). QakBot technical analysis. Retrieved September 27, 2021.
Open source URL - [11]Hunt Sea Turtle 2024
Hunt & Hackett Research Team. (2024, January 5). Turkish espionage campaigns in the Netherlands. Retrieved November 20, 2024.
Open source URL - [12]GitHub Pupy
Nicolas Verdier. (n.d.). Retrieved January 29, 2018.
Open source URL - [13]FireEye CARBANAK June 2017
Bennett, J., Vengerik, B. (2017, June 12). Behind the CARBANAK Backdoor. Retrieved June 11, 2018.
Open source URL - [14]Mandiant APT1
Mandiant. (n.d.). APT1 Exposing One of China’s Cyber Espionage Units. Retrieved July 18, 2016.
Open source URL - [15]Proofpoint Operation Transparent Tribe March 2016
Huss, D. (2016, March 1). Operation Transparent Tribe. Retrieved June 8, 2016.
Open source URL - [16]McAfee Night Dragon
McAfee® Foundstone® Professional Services and McAfee Labs™. (2011, February 10). Global Energy Cyberattacks: “Night Dragon”. Retrieved February 19, 2018.
Open source URL - [17]Github PowerShell Empire
Schroeder, W., Warner, J., Nelson, M. (n.d.). Github PowerShellEmpire. Retrieved April 28, 2016.
Open source URL - [18]NCC Group Chimera January 2021
Jansen, W . (2021, January 12). Abusing cloud services to fly under the radar. Retrieved September 12, 2024.
Open source URL - [19]Cybereason Kimsuky November 2020
Dahan, A. et al. (2020, November 2). Back to the Future: Inside the Kimsuky KGH Spyware Suite. Retrieved November 6, 2020.
Open source URL - [20]FireEye APT35 2018
Mandiant. (2018). Mandiant M-Trends 2018. Retrieved November 17, 2024.
Open source URL - [21]F-Secure Cosmicduke
F-Secure Labs. (2014, July). COSMICDUKE Cosmu with a twist of MiniDuke. Retrieved July 3, 2014.
Open source URL - [22]Trend Micro Muddy Water March 2021
Peretz, A. and Theck, E. (2021, March 5). Earth Vetala – MuddyWater Continues to Target Organizations in the Middle East. Retrieved March 18, 2021.
Open source URL - [23]ESET MirrorFace DEC 2022
Breitenbacher, D. (2022, December 14). Unmasking MirrorFace: Operation LiberalFace targeting Japanese political entities. Retrieved April 17, 2026.
Open source URL - [24]ESET WinterVivern 2023
Matthieu Faou. (2023, October 25). Winter Vivern exploits zero-day vulnerability in Roundcube Webmail servers. Retrieved July 29, 2024.
Open source URL - [25]CIS Emotet Dec 2018
CIS. (2018, December 12). MS-ISAC Security Primer- Emotet. Retrieved March 25, 2019.
Open source URL - [26]Microsoft Outlook Files
Microsoft. (n.d.). Introduction to Outlook Data Files (.pst and .ost). Retrieved February 19, 2020.
Open source URL - [27]Microsoft Outlook Files
Microsoft. (n.d.). Introduction to Outlook Data Files (.pst and .ost). Retrieved February 19, 2020.
Open source URL - [28]Outlook File Sizes
N. O'Bryan. (2018, May 30). Managing Outlook Cached Mode and OST File Sizes. Retrieved February 19, 2020.
Open source URL - [29]Outlook File Sizes
N. O'Bryan. (2018, May 30). Managing Outlook Cached Mode and OST File Sizes. Retrieved February 19, 2020.
Open source URL - [30]mitre-attackT1114.001Open source URL
- [31]mitre-attackT1114.001Open source URL
- [32]mitre-attackT1114.001Open source URL
- [33]ESET Turla Lunar toolset May 2024
Jurčacko, F. (2024, May 15). To the Moon and back(doors): Lunar landing in diplomatic missions. Retrieved June 26, 2024.
Open source URL - [34]Palo Alto Ashen Lepus DEC 2025
Unit 42. (2025, December 11). Hamas-Affiliated Ashen Lepus Targets Middle Eastern Diplomatic Entities With New AshTag Malware Suite. Retrieved April 20, 2026.
Open source URL - [35]group-ib_redcurl1
Group-IB. (2020, August). RedCurl: The Pentest You Didn’t Know About. Retrieved August 9, 2024.
Open source URL - [36]TrustedSec OOB Communications
Tyler Hudak. (2022, December 29). To OOB, or Not to OOB?: Why Out-of-Band Communications are Essential for Incident Response. Retrieved August 30, 2024.
Open source URL - [37]Talos Smoke Loader July 2018
Baker, B., Unterbrink H. (2018, July 03). Smoking Guns - Smoke Loader learned new tricks. Retrieved July 5, 2018.
Open source URL - [38]Kaspersky QakBot September 2021
Kuzmenko, A. et al. (2021, September 2). QakBot technical analysis. Retrieved September 27, 2021.
Open source URL - [39]Kroll Qakbot June 2020
Sette, N. et al. (2020, June 4). Qakbot Malware Now Exfiltrating Emails for Sophisticated Thread Hijacking Attacks. Retrieved September 27, 2021.
Open source URL - [40]Trend Micro Qakbot December 2020
Trend Micro. (2020, December 17). QAKBOT: A decade-old malware still with new tricks. Retrieved November 17, 2024.
Open source URL - [41]Hunt Sea Turtle 2024
Hunt & Hackett Research Team. (2024, January 5). Turkish espionage campaigns in the Netherlands. Retrieved November 20, 2024.
Open source URL - [42]GitHub Pupy
Nicolas Verdier. (n.d.). Retrieved January 29, 2018.
Open source URL - [43]FireEye CARBANAK June 2017
Bennett, J., Vengerik, B. (2017, June 12). Behind the CARBANAK Backdoor. Retrieved June 11, 2018.
Open source URL - [44]Mandiant APT1
Mandiant. (n.d.). APT1 Exposing One of China’s Cyber Espionage Units. Retrieved July 18, 2016.
Open source URL - [45]Proofpoint Operation Transparent Tribe March 2016
Huss, D. (2016, March 1). Operation Transparent Tribe. Retrieved June 8, 2016.
Open source URL - [46]McAfee Night Dragon
McAfee® Foundstone® Professional Services and McAfee Labs™. (2011, February 10). Global Energy Cyberattacks: “Night Dragon”. Retrieved February 19, 2018.
Open source URL - [47]Github PowerShell Empire
Schroeder, W., Warner, J., Nelson, M. (n.d.). Github PowerShellEmpire. Retrieved April 28, 2016.
Open source URL - [48]NCC Group Chimera January 2021
Jansen, W . (2021, January 12). Abusing cloud services to fly under the radar. Retrieved September 12, 2024.
Open source URL - [49]Cybereason Kimsuky November 2020
Dahan, A. et al. (2020, November 2). Back to the Future: Inside the Kimsuky KGH Spyware Suite. Retrieved November 6, 2020.
Open source URL - [50]FireEye APT35 2018
Mandiant. (2018). Mandiant M-Trends 2018. Retrieved November 17, 2024.
Open source URL - [51]F-Secure Cosmicduke
F-Secure Labs. (2014, July). COSMICDUKE Cosmu with a twist of MiniDuke. Retrieved July 3, 2014.
Open source URL - [52]Trend Micro Muddy Water March 2021
Peretz, A. and Theck, E. (2021, March 5). Earth Vetala – MuddyWater Continues to Target Organizations in the Middle East. Retrieved March 18, 2021.
Open source URL
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