Technical Analysis of GuLoader Obfuscation Techniques
Essential information
- Published
- 09/02/2026 19:07
- Modified
- 09/02/2026 20:42
- Tags
- 2026-02-09 anti-analysis cloudeye downloader exception-handling guloader obfuscation payload-decryption polymorphic-code string encryption
- Related entities
- 6 observables, 14 techniques (mitre), 2 malware
Description
GuLoader, a malware downloader active since 2019, primarily delivers RATs and information stealers. It employs sophisticated anti-analysis techniques, including polymorphic code for dynamic constant construction and complex exception-based control flow obfuscation. The malware has evolved to handle multiple exception types, making tracing its execution flow challenging. GuLoader uses dynamic hashing, encrypted strings, and stack-based string encryption to conceal critical information. It often hosts payloads on trusted cloud services to bypass reputation-based detection. The malware's consistent development and updating of anti-analysis techniques suggest it will remain a significant threat in the future.