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MITRE ATT&CK® Technique

T1539: Steal Web Session Cookie

An adversary may steal web application or service session cookies and use them to gain access to web applications or Internet services as an authenticated user without needing credentials. Web applications and services often use session cookies as an authentication token after a user has authenticated to a website.

Cookies are often valid for an extended period of time, even if the web application is not actively used. Cookies can be found on disk, in the process memory of the browser, and in network traffic to remote systems. Additionally, other applications on the targets machine might store sensitive authentication cookies in memory (e.g. apps which authenticate to cloud services). Session cookies can be used to bypasses some multi-factor authentication protocols.[1]

There are several examples of malware targeting cookies from web browsers on the local system.[2][3] Adversaries may also steal cookies by injecting malicious JavaScript content into websites or relying on User Execution by tricking victims into running malicious JavaScript in their browser.[4][5]

There are also open source frameworks such as `Evilginx2` and `Muraena` that can gather session cookies through a malicious proxy (e.g., Adversary-in-the-Middle) that can be set up by an adversary and used in phishing campaigns.[6][7]

After an adversary acquires a valid cookie, they can then perform a Web Session Cookie technique to login to the corresponding web application.

EnterpriseT1539TechniqueObject v1.5Modified
Glexia's Take · Automated analysis

Security context for executives and security teams

Automation confidenceMedium

T1539: Steal Web Session Cookie describes An adversary may steal web application or service session cookies and use them to gain access to web applications or Internet services as an authenticated user without needing credentials. Web applications and services often use session cookies as an authentication token after a user has authenticated to a website. Cookies are often valid for an extended period of time, even if the web application is not actively used. Cookies can be found on disk, in the process memory of the browser, and in network traffic to rem...

Executive priority

T1539: Steal Web Session Cookie is an official MITRE ATT&CK technique. Glexia treats it as defensive behavior context for prioritizing monitoring, control validation, and response planning without using the object by itself as an attribution claim.

Technical view

Security teams should validate T1539: Steal Web Session Cookie by reviewing the official ATT&CK relationships, mapped tactics (credential-access), supported platforms (Linux, macOS, Office Suite, SaaS), and available local telemetry before making detection or mitigation decisions.

Likely telemetry

  • Official ATT&CK relationships and object metadata
  • Identity, privilege, and authentication events
  • Network, endpoint, and security-tool telemetry

Detection direction

  • Validate whether T1539: Steal Web Session Cookie appears in your detection coverage and tabletop scenarios.
  • Use the object to align executive risk language with SOC, incident response, and detection engineering work.
  • Do not treat ATT&CK relationship context as attribution without corroborating evidence.

Mitigation priorities

  • Map the object to existing controls and identify missing telemetry or response ownership.
  • Prioritize mitigations that reduce exposure on the listed platforms and tactics.
  • Review adjacent ATT&CK relationships before changing policy, detections, or reporting language.
Additional notes and limits

Baseline Glexia take generated from the official MITRE ATT&CK STIX object, source hash, tactics, platforms, and detection fields. It is safe to replace with a richer model-generated take for the same source hash later.

This baseline take is source-grounded and schema-validated, but it does not include environment-specific telemetry, incident evidence, or threat-intelligence corroboration.

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Official MITRE ATT&CK definition

Steal Web Session Cookie

An adversary may steal web application or service session cookies and use them to gain access to web applications or Internet services as an authenticated user without needing credentials. Web applications and services often use session cookies as an authentication token after a user has authenticated to a website.

Cookies are often valid for an extended period of time, even if the web application is not actively used. Cookies can be found on disk, in the process memory of the browser, and in network traffic to remote systems. Additionally, other applications on the targets machine might store sensitive authentication cookies in memory (e.g. apps which authenticate to cloud services). Session cookies can be used to bypasses some multi-factor authentication protocols.[1]

There are several examples of malware targeting cookies from web browsers on the local system.[2][3] Adversaries may also steal cookies by injecting malicious JavaScript content into websites or relying on User Execution by tricking victims into running malicious JavaScript in their browser.[4][5]

There are also open source frameworks such as `Evilginx2` and `Muraena` that can gather session cookies through a malicious proxy (e.g., Adversary-in-the-Middle) that can be set up by an adversary and used in phishing campaigns.[6][7]

After an adversary acquires a valid cookie, they can then perform a Web Session Cookie technique to login to the corresponding web application.

View the same entry on attack.mitre.org (MITRE-hosted reference; in-page links above use the Glexia ATT&CK library.)

Glexia analysis

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.

Associated objects

Groups, software, and campaigns

GroupEnterprise

G0094: Kimsuky

Kimsuky is a Democratic People's Republic of Korea (DPRK)-based cyber espionage group that has been active since at least 2012. The group initially targeted South Korean government agencies, think tanks, and subject-matter experts in various fields. Its operations expanded to include the United Nations and organizations in the government, education, business services, and manufacturing sectors across the United States, Japan, Russia, and Europe. Kimsuky has focused collection on foreign policy and national security issues tied to the Korean Peninsula, nuclear policy, and sanctions. Kimsuky operations have overlapped with those of other North Korean state-sponsored cyber espionage actors as a result of ad hoc collaborations or other limited resource sharing.[1][2][3][4][5][6]

Kimsuky was assessed to be responsible for the 2014 Korea Hydro & Nuclear Power Co. compromise; other notable campaigns include Operation STOLEN PENCIL (2018), Operation Kabar Cobra (2019), and Operation Smoke Screen (2019).[7][8][9] In 2023, Kimsuky was observed using commercial large language models (LLMs) to assist with vulnerability research, scripting, social engineering and reconnaissance.[10]

DPRK threat actor cluster boundaries overlap in open source reporting, with some security researchers consolidating all attributed North Korean state-sponsored cyber activity under Lazarus Group, rather than tracking operationally distinct subgroups.

GroupEnterprise

G0034: Sandworm Team

Sandworm Team is a destructive threat group that has been attributed to Russia's General Staff Main Intelligence Directorate (GRU) Main Center for Special Technologies (GTsST) military unit 74455.[1][2] This group has been active since at least 2009.[3][4][5][6]

In October 2020, the US indicted six GRU Unit 74455 officers associated with Sandworm Team for the following cyber operations: the 2015 and 2016 attacks against Ukrainian electrical companies and government organizations, the 2017 worldwide NotPetya attack, targeting of the 2017 French presidential campaign, the 2018 Olympic Destroyer attack against the Winter Olympic Games, the 2018 operation against the Organisation for the Prohibition of Chemical Weapons, and attacks against the country of Georgia in 2018 and 2019.[1][2] Some of these were conducted with the assistance of GRU Unit 26165, which is also referred to as APT28.[7]

GroupEnterprise

G1015: Scattered Spider

Scattered Spider is a native English-speaking cybercriminal group active since at least 2022. [1] [2] The group initially targeted customer relationship management (CRM) providers, business process outsourcing (BPO) firms, and telecommunications and technology companies before expanding in 2023 to gaming, hospitality, retail, managed service provider (MSP), manufacturing, and financial sectors. [2] Scattered Spider relies heavily on social engineering, including impersonating IT and help-desk staff, to gain initial access, bypass multi-factor authentication (MFA), and compromise enterprise networks. The group has adapted its tooling to evade endpoint detection and response (EDR) defenses and used ransomware for financial gain. [3] [4] [5] Scattered Spider had expanded into hybrid cloud and identity environments, using help-desk impersonation and MFA bypass to obtain administrator access in Okta, AWS, and Office 365. [6]

GroupEnterprise

G1033: Star Blizzard

Star Blizzard is a cyber espionage and influence group originating in Russia that has been active since at least 2019. Star Blizzard campaigns align closely with Russian state interests and have included persistent phishing and credential theft against academic, defense, government, NGO, and think tank organizations in NATO countries, particularly the US and the UK.[1][2][3][4]

GroupEnterprise

G1014: LuminousMoth

LuminousMoth is a Chinese-speaking cyber espionage group that has been active since at least October 2020. LuminousMoth has targeted high-profile organizations, including government entities, in Myanmar, the Philippines, Thailand, and other parts of Southeast Asia. Some security researchers have concluded there is a connection between LuminousMoth and Mustang Panda based on similar targeting and TTPs, as well as network infrastructure overlaps.[1][2]

GroupEnterprise

G1044: APT42

APT42 is an Iranian-sponsored threat group that conducts cyber espionage and surveillance.[1] The group primarily focuses on targets in the Middle East region, but has targeted a variety of industries and countries since at least 2015.[1] APT42 starts cyber operations through spearphishing emails and/or the PINEFLOWER Android malware, then monitors and collects information from the compromised systems and devices.[1] Finally, APT42 exfiltrates data using native features and open-source tools.[2]

APT42 activities have been linked to Magic Hound by other commercial vendors. While there are behavior and software overlaps between Magic Hound and APT42, they appear to be distinct entities and are tracked as separate entities by their originating vendor.

MalwareEnterprise

S1201: TRANSLATEXT

TRANSLATEXT is malware that is believed to be used by Kimsuky.[1] TRANSLATEXT masqueraded as a Google Translate extension for Google Chrome, but is actually a collection of four malicious Javascript files that perform defense evasion, information collection and exfiltration.[1]

Windows
MalwareEnterprise

S1111: DarkGate

DarkGate first emerged in 2018 and has evolved into an initial access and data gathering tool associated with various criminal cyber operations. Written in Delphi and named "DarkGate" by its author, DarkGate is associated with credential theft, cryptomining, cryptotheft, and pre-ransomware actions.[1] DarkGate use increased significantly starting in 2022 and is under active development by its author, who provides it as a Malware-as-a-Service offering.[2]

Windows
MalwareEnterprise

S0631: Chaes

Chaes is a multistage information stealer written in several programming languages that collects login credentials, credit card numbers, and other financial information. Chaes was first observed in 2020, and appears to primarily target victims in Brazil as well as other e-commerce customers in Latin America.[1]

Windows
MalwareEnterprise

S9020: LODEINFO

LODEINFO is a fileless backdoor malware first identified in 2020 that has been used by actors including MirrorFace, primarily against media, diplomatic, governmental, and public sector organizations in Japan.[1][2][3]

Windows
MalwareEnterprise

S9010: GlassWorm

GlassWorm is a worm that propagated through supply chain attacks by compromising repository credentials from victim environments and having malicious payloads added to those compromised accounts for distribution to victims across the various development ecosystems.[1][2][3] GlassWorm has numerous variants, including Rust binaries, encrypted JavaScript and a variant leveraging invisible Unicode characters that made reverse engineering difficult.[4][1][5] GlassWorm has employed a unique command and control (C2) methodology using Solana blockchain.[6][1] GlassWorm was first reported in October 2025.[6][1][3]

macOSWindows
MalwareEnterprise

S1240: RedLine Stealer

RedLine Stealer is an information-stealer malware variant first identified in 2020.[1][2][3] RedLine Stealer is a Malware as a Service (MaaS) and was reportedly sold as either a one-time purchase or a monthly subscription service.[1][4] Information obtained from RedLine Stealer has been known to be sold on the deep and dark web to Initial Access Brokers (IABs), who use or resell the stolen credentials for further intrusions.[5][4]

Windows
MalwareEnterprise

S0531: Grandoreiro

Grandoreiro is a banking trojan written in Delphi that was first observed in 2016 and uses a Malware-as-a-Service (MaaS) business model. Grandoreiro has confirmed victims in Brazil, Mexico, Portugal, and Spain.[1][2]

Windows
MalwareEnterprise

S1207: XLoader

XLoader is an infostealer malware in use since at least 2016. Previously known and sometimes still referred to as Formbook, XLoader is a Malware as a Service (MaaS) known for stealing data from web browsers, email clients and File Transfer Protocol (FTP) applications.[1][2][3][4][5]

Windows
CampaignEnterprise

C0024: SolarWinds Compromise

The SolarWinds Compromise was a sophisticated supply chain cyber operation conducted by APT29 that was discovered in mid-December 2020. APT29 used customized malware to inject malicious code into the SolarWinds Orion software build process that was later distributed through a normal software update; they also used password spraying, token theft, API abuse, spear phishing, and other supply chain attacks to compromise user accounts and leverage their associated access. Victims of this campaign included government, consulting, technology, telecom, and other organizations in North America, Europe, Asia, and the Middle East. This activity has been labled the StellarParticle campaign in industry reporting.[1] Industry reporting also initially referred to the actors involved in this campaign as UNC2452, NOBELIUM, Dark Halo, and SolarStorm.[2][3][4][5][1][6][7][8]

In April 2021, the US and UK governments attributed the SolarWinds Compromise to Russia's Foreign Intelligence Service (SVR); public statements included citations to APT29, Cozy Bear, and The Dukes.[9][10][11] The US government assessed that of the approximately 18,000 affected public and private sector customers of Solar Winds’ Orion product, a much smaller number were compromised by follow-on APT29 activity on their systems.[12]

Relationship explorer

All related ATT&CK context

Mitigations

Mitigation direction

Change history

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.

ATT&CK release
19.2
Object version
1.5
Created
Modified
Raw hash
46590843583f53de...
Imported snapshots across ATT&CK releases(2)
ReleaseBundle importedObject versionModifiedStatusRaw hash
19.21.5Current bundle46590843583f…
19.11.5Older bundle46590843583f…
Raw source

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.

Source references

External references and citations

MITRE external references are preserved separately from Glexia analysis so citations remain traceable to their original source records.

  1. [1]
    Pass The Cookie

    Rehberger, J. (2018, December). Pivot to the Cloud using Pass the Cookie. Retrieved April 5, 2019.

    Open source URL
  2. [2]
    Kaspersky TajMahal April 2019

    GReAT. (2019, April 10). Project TajMahal – a sophisticated new APT framework. Retrieved October 14, 2019.

    Open source URL
  3. [3]
    Unit 42 Mac Crypto Cookies January 2019

    Chen, Y., Hu, W., Xu, Z., et. al. (2019, January 31). Mac Malware Steals Cryptocurrency Exchanges’ Cookies. Retrieved October 14, 2019.

    Open source URL
  4. [4]
    Talos Roblox Scam 2023

    Tiago Pereira. (2023, November 2). Attackers use JavaScript URLs, API forms and more to scam users in popular online game “Roblox”. Retrieved January 2, 2024.

    Open source URL
  5. [5]
    Krebs Discord Bookmarks 2023

    Brian Krebs. (2023, May 30). Discord Admins Hacked by Malicious Bookmarks. Retrieved January 2, 2024.

    Open source URL
  6. [6]
    Github evilginx2

    Gretzky, Kuba. (2019, April 10). Retrieved October 8, 2019.

    Open source URL
  7. [7]
    GitHub Mauraena

    Orrù, M., Trotta, G.. (2019, September 11). Muraena. Retrieved October 14, 2019.

    Open source URL
  8. [8]
    mitre-attackT1539
    Open source URL
Source and licensing

Source: MITRE ATT&CK®. © 2026 The MITRE Corporation. This work is reproduced and distributed with the permission of The MITRE Corporation. MITRE ATT&CK and ATT&CK are registered trademarks of The MITRE Corporation. Glexia is not affiliated with or endorsed by MITRE.