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Odd question. Why would a webviewer be safer in this case? edit: Thank you for both answers. I thought it had to do with sandbox rationale, but couldn't mental

Odd question. Why would a webviewer be safer in this case? edit: Thank you for both answers. I thought it had to do with sandbox rationale, but couldn't mentally get past the fact that sandbox could potentially be escaped too. Eh, I think it is time for sleep.

mettamage 7y ago
Well is it safe? Don't know. Safer: definitely. Given that the collective amount of PDF attacks is some number, now this particular PDF needs to attack PDF and the webviewer. Assuming that 1% of all PDFs do that, I'd say it's 100 times safer than not using a webviewer. If you still think that 1% of all potential PDF attacks is too unsafe, then that's a different discussion. If you think my 1% is off, then that's a different discussion too. All I'm saying is that it's safer.
- saagarjha 7y ago
  Well, PDF attacks need to attack the viewer you're using too…
  - mettamage 7y ago
    True, but in most cases this is assumed to be a popular PDF reader. If it is specifically targeting a webviewer, I agree. But that still means that there is some JS PDF parser in between, though that provides very little in terms of security, I doubt that such a parser will check for malicious input.
    - heeen2 7y ago
      Afaik chromium uses the same pdf renderer as foxit (pdfium)
    - pbhjpbhj 7y ago
      >a popular PDF reader What's the most popular, Chrome browser I'd have thought?
gliese1337 7y ago
If it's rendering locally, at least the browser is sandboxed. And if it's rendering server-side, then at worst someone else's machine gets compromised instead of yours.
intherdfield 7y ago
On macOS, the PDF reader Preview.app runs sandboxed by default. The Preview.app sandbox is not quite as secure as what is used by browsers such as Firefox or Chrome on macOS for web content, so there is probably still a benefit to viewing PDFs in the browser, depending on whether the browser or PDF viewer is more hardened against these attacks.

mettamage 7y ago

Well is it safe? Don't know. Safer: definitely. Given that the collective amount of PDF attacks is some number, now this particular PDF needs to attack PDF and the webviewer. Assuming that 1% of all PDFs do that, I'd say it's 100 times safer than not using a webviewer. If you still think that 1% of all potential PDF attacks is too unsafe, then that's a different discussion. If you think my 1% is off, then that's a different discussion too. All I'm saying is that it's safer.

saagarjha 7y ago
Well, PDF attacks need to attack the viewer you're using too…
- mettamage 7y ago
  True, but in most cases this is assumed to be a popular PDF reader. If it is specifically targeting a webviewer, I agree. But that still means that there is some JS PDF parser in between, though that provides very little in terms of security, I doubt that such a parser will check for malicious input.
  - heeen2 7y ago
    Afaik chromium uses the same pdf renderer as foxit (pdfium)
  - pbhjpbhj 7y ago
    >a popular PDF reader What's the most popular, Chrome browser I'd have thought?

gliese1337 7y ago

If it's rendering locally, at least the browser is sandboxed. And if it's rendering server-side, then at worst someone else's machine gets compromised instead of yours.

intherdfield 7y ago

On macOS, the PDF reader Preview.app runs sandboxed by default. The Preview.app sandbox is not quite as secure as what is used by browsers such as Firefox or Chrome on macOS for web content, so there is probably still a benefit to viewing PDFs in the browser, depending on whether the browser or PDF viewer is more hardened against these attacks.