Proxy: Domain Fronting
- ID
- T1090.004
- Tactics
- TA0011 Command and Control
- Sub-technique of
- T1090 Proxy
- Platforms
- Linux, macOS, Windows, ESXi
- Data sources
- Network Traffic Content, Network Connection Creation, Process Creation
- Source
- attack.mitre.org
- MITRE last modified
- 25 Oct 2025
Adversaries may take advantage of routing schemes in Content Delivery Networks (CDNs) and other services which host multiple domains to obfuscate the intended destination of HTTPS traffic or traffic tunneled through HTTPS. [1] Domain fronting involves using different domain names in the SNI field of the TLS header and the Host field of the HTTP header. If both domains are served from the same CDN, then the CDN may route to the address specified in the HTTP header after unwrapping the TLS header. A variation of the the technique, "domainless" fronting, utilizes a SNI field that is left blank; this may allow the fronting to work even when the CDN attempts to validate that the SNI and HTTP Host fields match (if the blank SNI fields are ignored).
For example, if domain-x and domain-y are customers of the same CDN, it is possible to place domain-x in the TLS header and domain-y in the HTTP header. Traffic will appear to be going to domain-x, however the CDN may route it to domain-y.
Detection
- DET0196 Domain Fronting Behavior via Mismatched TLS SNI and HTTP Host Headers
Data components: Network Traffic Content, Network Connection Creation, Process Creation
Mitigations (1)
- M1020 SSL/TLS Inspection
If it is possible to inspect HTTPS traffic, the captures can be analyzed for connections that appear to be domain fronting.