Threats Tagged 'microsoft 365 compromise'

Arctic Wolf Labs has been tracking multiple campaigns built around CastleLoader, a multi-stage shellcode loader that has evolved significantly. Three distinct campaigns were identified: Urutyka, Garrigin, and Noidret. The most significant development is the integration of NeedleStealer framework payloads, marking the first observed use of Rust and Golang tooling in this campaign cluster. NeedleStealer includes a Rust-based desktop cryptocurrency wallet spoofer targeting Ledger, Trezor, and Exodus wallets, and a Golang-based malicious browser extension installer. The campaigns utilize obfuscated PowerShell stagers, IronPython runtimes, and NodeJS-based shellcode injectors. Infrastructure analysis revealed consistent naming patterns, staged domains for future operations, and the use of fraudulently obtained code-signing certificates. The campaigns consistently deploy NetSupport RAT and CastleStealer alongside the new NeedleStealer payloads, suggesting an expansion toward high-value cryptocurrency targeting.

HighVulnerabilityUnited StatesCanada#cve#cve-2026-0257#cwe-565

Device code phishing exploits the OAuth 2.0 device authorization grant, a legitimate authentication feature designed for input-limited devices like smart TVs. Attackers initiate a device-code request with Microsoft, receive a valid code, then trick victims into approving it through social engineering. The victim authenticates on genuine Microsoft pages and completes MFA, but the session tokens are issued to the attacker instead. When targeting the Microsoft Authentication Broker, attackers can register rogue devices and obtain long-lived refresh tokens for persistent access. A recent campaign used sophisticated multi-stage delivery chains involving Google Sites, compromised website redirectors, and fake document-sharing portals. After successful authentication, attackers registered multiple devices, created hidden mailbox rules, and used compromised accounts to send additional phishing emails, all without touching victim endpoints.

EvilTokens is a sophisticated phishing kit that conceals critical components of its attack through browser-side AES-GCM encryption, creating visibility gaps for traditional static URL analysis. The kit exploits Microsoft's legitimate device login flow through OAuth device-code phishing to gain account access without directly stealing passwords. Targeting organizations primarily in the United States and Europe, EvilTokens focuses on managed security services, technology, manufacturing, education, banking, and consulting sectors. The encrypted landing page only reveals its malicious content after browser decryption, requiring dynamic analysis to uncover the complete attack chain. The kit uses multiple stages including gate checks, user code requests, and session monitoring to complete Microsoft 365 account takeovers while appearing legitimate through final redirects to OneDrive.

MediumMalwareUnited States#oauth device-code phishing#dom manipulation#microsoft 365 compromise