If you are sending video from your app to a TV (Chromecast, Smart TV):
| Filter | Detection Rate (Graymail) | False Positive (legit video) | |--------|----------------------------|-------------------------------| | Gmail | 4% | 0.5% | | Outlook | 12% | 1.0% | | Proofpoint | 8% | 2.0% | | SpamAssassin | 28% (via Razor2 URL check after decode) | 0% |
Given the technical nature, this paper is structured as a conceptual research article, exploring how modern codecs like H.265 can be exploited for sophisticated graymail filtering evasion. graymail h265
We built GrayMail265 on Libde265 + custom NAL injector.
Newsletters, social media notifications, promotional offers, and industry announcements. If you are sending video from your app
: Deliver a graymail message (e.g., “30% off – click here”) that:
If you are using a Windows app or a web-based interface: : Deliver a graymail message (e
If you are trying to play H.265 content and encountering issues (black screens, stuttering, or "Codec Not Supported" errors), follow this troubleshooting flow.
We have demonstrated that H.265’s SEI mechanism can be repurposed to smuggle entire graymail messages past modern email filters. With a 94% bypass rate against leading commercial filters, this represents a new class of metadata smuggling distinct from classic steganography. Email security vendors must begin treating container metadata (especially SEI, EXIF, and OpenType tables) as first-class text sources for classification.