Tell me more ×
Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.
up vote 1 down vote favorite

I tried to send someone an email with a PNG format image attachment but it was stopped by their email filtering software (messagelabs).

They said I could send them the image in a JPG or ZIP format file.

I'm assuming they are blocking this format for security reasons. But, what about the PNG format is potentially unsafe?

Are there any known security vulnerabilites in it? (I've only found something very old.)

Is it possible to include executable or other malicious code in the format?

share|improve this question
Pretty much any file format can be used to breach security. – Daniel Beck♦ Dec 9 '10 at 17:36

2 Answers

up vote 4 down vote accepted

It's more likely that they have a whitelist allowing certain extensions, as opposed to a blacklist blocking certain extensions. It's easier to maintain for them and lowers the vector of attack for them.

share|improve this answer
you could have upset their image/content control setting. – mic84 Dec 9 '10 at 17:59
1  
+1 as this is typically what I would expect to see messagelabs do on request. They will have a list of the file types their client wants, and block everything else. – Rory Alsop Dec 9 '10 at 18:01
up vote 1 down vote

At least one vulnerability was actually announced for this a few years ago: US-CERT: Microsoft Internet Explorer buffer overflow in PNG image rendering component. HTML e-mail with PNGs was a possible attack vector.

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.