Applied Cybernetics Group
T1539 Steal Web Session Cookie
- Technique
T1539- Tactics
- Credential Access
- Research, 90 days
- 5
- KEV CVEs mapped
- 0
- SigmaHQ rules
- 2
- Elastic, Splunk
- 20
- thrunt rules
- 0
- Upstream
- https://attack.mitre.org/techniques/T1539
MITRE description
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.(Citation: Pass The Cookie) There are several examples of malware targeting cookies from web browsers on the local system.(Citation: Kaspersky TajMahal April 2019)(Citation: Unit 42 Mac Crypto Cookies January 2019) Adversaries may also steal cookies by injecting malicious JavaScript content into websites or relying on [User Execution](https://attack.mitre.org/techniques/T1204) by tricking victims into running malicious JavaScript in their browser.(Citation: Talos Roblox Scam 2023)(Citation: Krebs Discord Bookmarks 2023) 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](https://attack.mitre.org/techniques/T1557)) that can be set up by an adversary and used in phishing campaigns.(Citation: Github evilginx2)(Citation: GitHub Mauraena) After an adversary acquires a valid cookie, they can then perform a [Web Session Cookie](https://attack.mitre.org/techniques/T1550/004) technique to log in to the corresponding web application.
Research citing this technique
Reports and advisories from the last 90 days that cite this technique.
-
2026-11-03ESET: Gorbag: Orcs at the border harvesting intelligence from Ukraine -
2026-10-22Group-IB: Inside SiriusQT: A Seriously Skilled RAT -
2026-10-08Zscaler ThreatLabz: Suspected TraderTraitor Group Uses Trojanized Terraform Provider to Deliver Cross-Platform Malware -
2026-08-25Group-IB: Balonx Sistema: El Rostro Detrás del PhaaS que Impacta la Banca Mexicana -
2026-08-19Group-IB: Balonx Sistema: The Face Behind the PhaaS Affecting Mexican Banking
Detection coverage
SigmaHQ community rules
Elastic and Splunk rules
- Potential Cookies Theft via Browser Debugging (elastic)
- Anthropic Session Reuse Impossible Travel (elastic)
- Anthropic User Activity From High Number of Countries (elastic)
- AWS IAM User Console Login from Multiple Geolocations (elastic)
- Entra ID Device-Bound PRT Replay via First-Party App from Unusual IP (elastic)
- Entra ID Device-Bound PRT from Unusual Device IP (elastic)
- Entra ID Microsoft Authentication Broker Sign-In with Non-Standard User Agent (elastic)
- Entra ID Potential AiTM Sign-In via OfficeHome (Tycoon2FA) (elastic)
- M365 Potential AiTM UserLoggedIn via Office App (Tycoon2FA) (elastic)
- Multiple Device Token Hashes for Single Okta Session (elastic)
- Okta Multiple OS Names Detected for a Single DT Hash (elastic)
- Okta AiTM Session Cookie Replay (elastic)
- OpenAI ChatGPT Enterprise User Activity From High Number of Countries (elastic)
- WebProxy Settings Modification (elastic)
- First Time Python Accessed Sensitive Credential Files (elastic)
- Suspicious Web Browser Sensitive File Access (elastic)
- Manual Loading of a Suspicious Chromium Extension (elastic)
- Browser Process Spawned from an Unusual Parent (elastic)
- Potential Entra ID PRT Extraction via BrowserCore (elastic)
- Okta Suspicious Use of a Session Cookie (splunk)