evenwicht

cross-posted from: https://lemmy.sdf.org/post/24645301

They emailed me a PDF. It opened fine with evince and looked like a simple doc at first. Then I clicked on a field in the form. Strangely, instead of simply populating the field with my text, a PDF note window popped up so my text entry went into a PDF note, which many viewers present as a sticky note icon.

If I were to fax this PDF, the PDF comments would just get lost. So to fill out the form I fed it to LaTeX and used the overpic pkg to write text wherever I choose. LaTeX rejected the file.. could not handle this PDF. Then I used the file command to see what I am dealing with:

$ file signature_page.pdf
signature_page.pdf: Java serialization data, version 5

WTF is that? I know PDF supports JavaScript (shitty indeed). Is that what this is? “Java” is not JavaScript, so I’m baffled. Why is java in a PDF? (edit: explainer on java serialization, and some analysis)

My workaround was to use evince to print the PDF to PDF (using a PDF-building printer driver or whatever evince uses), then feed that into LaTeX. That worked.

My question is, how common is this? Is it going to become a mechanism to embed a tracking pixel like corporate assholes do with HTML email?

I probably need to change my habits. I know PDF docs can serve as carriers of copious malware anyway. Some people go to the extreme of creating a one-time use virtual machine with PDF viewer which then prints a PDF to a PDF before destroying the VM which is assumed to be compromised.

My temptation is to take a less tedious approach. E.g. something like:

$ firejail --net=none evince untrusted.pdf

I should be able to improve on that by doing something non-interactive. My first guess:

$ firejail --net=none gs -sDEVICE=pdfwrite -q -dFIXEDMEDIA -dSCALE=1 -o is_this_output_safe.pdf -- /usr/share/ghostscript/*/lib/viewpbm.ps untrusted_input.pdf

output:

Error: /invalidfileaccess in --file--
Operand stack:
   (untrusted_input.pdf)   (r)
Execution stack:
   %interp_exit   .runexec2   --nostringval--   --nostringval--   --nostringval--   2   %stopped_push   --nostringval--   --nostringval--   --nostringval--   false   1   %stopped_push   1990   1   3   %oparray_pop   1989   1   3   %oparray_pop   1977   1   3   %oparray_pop   1833   1   3   %oparray_pop   --nostringval--   %errorexec_pop   .runexec2   --nostringval--   --nostringval--   --nostringval--   2   %stopped_push   --nostringval--   --nostringval--   --nostringval--   %array_continue   --nostringval--
Dictionary stack:
   --dict:769/1123(ro)(G)--   --dict:0/20(G)--   --dict:87/200(L)--   --dict:0/20(L)--
Current allocation mode is local
Last OS error: Permission denied
Current file position is 10479
GPL Ghostscript 10.00.0: Unrecoverable error, exit code 1

What’s my problem? Better ideas? I would love it if attempts to reach the cloud could be trapped and recorded to a log file in the course of neutering the PDF.

(note: I also wonder what happens when Firefox opens this PDF considering Mozilla is happy to blindly execute whatever code it receives no matter the context.)

They emailed me a PDF. It opened fine with evince and looked like a simple doc at first. Then I clicked on a field in the form. Strangely, instead of simply populating the field with my text, a PDF note window popped up so my text entry went into a PDF note, which many viewers present as a sticky note icon.

If I were to fax this PDF, the PDF comments would just get lost. So to fill out the form I fed it to LaTeX and used the overpic pkg to write text wherever I choose. LaTeX rejected the file.. could not handle this PDF. Then I used the file command to see what I am dealing with:

$ file signature_page.pdf
signature_page.pdf: Java serialization data, version 5

WTF is that? I know PDF supports JavaScript (shitty indeed). Is that what this is? My workaround was to use evince to print the PDF to PDF (using a PDF-building printer driver or whatever evince uses), then feed that into LaTeX. That worked.

My question is, how common is this? Is it going to become a mechanism to embed a tracking pixel like corporate assholes do with HTML email?

I probably need to change my habits. I know PDF docs can serve as carriers of copious malware anyway. Some people go to the extreme of creating a one-time use virtual machine with PDF viewer which then prints a PDF to a PDF before destroying the VM which is assumed to be compromised.

My temptation is to take a less tedious approach. E.g. something like:

$ firejail --net=none evince untrusted.pdf

I should be able to improve on that by doing something non-interactive. My first guess:

$ firejail --net=none gs -sDEVICE=pdfwrite -q -dFIXEDMEDIA -dSCALE=1 -o is_this_output_safe.pdf -- /usr/share/ghostscript/*/lib/viewpbm.ps untrusted_input.pdf

output:

Error: /invalidfileaccess in --file--
Operand stack:
   (untrusted_input.pdf)   (r)
Execution stack:
   %interp_exit   .runexec2   --nostringval--   --nostringval--   --nostringval--   2   %stopped_push   --nostringval--   --nostringval--   --nostringval--   false   1   %stopped_push   1990   1   3   %oparray_pop   1989   1   3   %oparray_pop   1977   1   3   %oparray_pop   1833   1   3   %oparray_pop   --nostringval--   %errorexec_pop   .runexec2   --nostringval--   --nostringval--   --nostringval--   2   %stopped_push   --nostringval--   --nostringval--   --nostringval--   %array_continue   --nostringval--
Dictionary stack:
   --dict:769/1123(ro)(G)--   --dict:0/20(G)--   --dict:87/200(L)--   --dict:0/20(L)--
Current allocation mode is local
Last OS error: Permission denied
Current file position is 10479
GPL Ghostscript 10.00.0: Unrecoverable error, exit code 1

What’s my problem? Better ideas? I would love it if attempts to reach the cloud could be trapped and recorded to a log file in the course of neutering the PDF.

I’ve noticed this problem on infosec.pub as well. If I edit a post and submit, the form is accepted but then the edits are simply scrapped. When I re-review my msg, the edits did not stick. This is a very old Lemmy bug I think going back over a year, but it’s bizarre how it’s non-reproducable. Some instances never have this problem but sdf and infosec trigger this bug unpredictably.

0.19.3 is currently the best Lemmy version but it still has this bug (just as 0.19.5 does). A good remedy would be to install an alternative front end, like alexandrite.

Political parties around the world have flocked to nationbuilder.com for some reason. This tor-hostile Cloudflare site is blocking Tor users from accessing election info. This kind of sloppy lazy web administration is common.

But what’s a bit disturbing is that when I contact a political party to say I cannot reach their page because of the nationbuilder block page, they sound surprised, like it’s the first time they are hearing about web problems. So Tor users are lazy too. That’s the problem.

cross-posted from: https://lemmy.sdf.org/post/24375297

Tracker pixels are surprisingly commonly used by legitimate senders.. your bank, your insurance company, any company you patronize. These assholes hide a 1-pixel image in HTML that tracks when you open your email and your IP (thus whereabouts).

I use a text-based mail client in part for this reason. But I got sloppy and opened an HTML attachment in a GUI browser without first inspecting the HTML. I inspected the code afterwards. Fuck me, I thought.. a tracker pixel. Then I visited just the hostname in my browser. Got a 403 Forbidden. I was happy to see that. Can I assume these idiots shot themselves in the foot with a firewall Tor blanket block? Or would the anti-tor firewall be smart enough to make an exception for tracker pixel URLs?

Tracker pixels are surprisingly commonly used by legitimate senders.. your bank, your insurance company, any company you patronize. These assholes hide a 1-pixel image in HTML that tracks when you open your email and your IP (thus whereabouts).

I use a text-based mail client in part for this reason. But I got sloppy and opened an HTML attachment in a GUI browser without first inspecting the HTML. I inspected the code afterwards. Fuck me, I thought.. a tracker pixel. Then I visited just the hostname in my browser. Got a 403 Forbidden. I was happy to see that. Can I assume these idiots shot themselves in the foot with a firewall Tor blanket block? Or would the anti-tor firewall be smart enough to make an exception for tracker pixel URLs?

A home insurance policy offers a discount to AAA members. The discount is the same amount as the cost of membership. I so rarely use a car or motorcycle that I would not benefit significantly from a roadside assistence plan. I cycle. But there are other discounts for AAA membership, like restaurant discounts. So my knee-jerk thought was: this is a no-brainer… I’m getting some benefits for free, in effect, so it just makes sense to get the membership.

Then I dug into AAA a bit more. The wiki shows beneficial and harmful things AAA has done. From the wiki, these points stand out to me:

Even though the roadside assistence is useless to me, the AAA membership comes with 2 more memberships. So I could give memberships to 2 family members and they would benefit from it. But it seems I need to drop this idea. AAA seems overall doing more harm than good.

(edit) And doesn’t it seem foolish to oppose mass transit even from the selfish car driver standpoint? If you drive a car, other cars are in your way slowing you down and also increasing your chances of simultaneously occupying the same space (crash). Surely you would benefit from others switching from car to public transport to give you more road space. It seems to me the anti mass transit move is AAA looking after it’s own interest in having more members paying dues.

I also noticed most AAA club’s websites block Tor. So the lack of privacy respect just made my decision to nix them even easier.

OSMand used to only crash 1 or 2 times per trip. It was usable enough. Now recently something changed with my config somehow and it shows extreme detail no matter how zoomed out I am. Every tiny street is being rendered. This is killing the app. It crashes so chronically it’s unusable.

Anyone know how to control this?

In “configure map” I have disabled everything except cycling routes. The “details” shows 0/9, which apparently only configures objects, not street details.

(edit) I think the “map magnifier” might be the issue. It was at 25% (the lowest), which I would intuitively think means less road detail. But it’s apparently counter-intuitive. I chose 100% and I seem to get less map detail -- which is what I need because the more detail, the more crashes. So I might have solved this.. need to experiment.

This is what my fetchmail log looks like today (UIDs and domains obfuscated):

fetchmail: starting fetchmail 6.4.37 daemon
fetchmail: Server certificate verification error: self-signed certificate in certificate chain
fetchmail: Missing trust anchor certificate: /C=US/O=Let's Encrypt/CN=R3
fetchmail: This could mean that the root CA's signing certificate is not in the trusted CA certificate location, or that c_rehash needs to be run on the certificate directory. For details, please see the documentation of --sslcertpath and --sslcertfile in the manual page. See README.SSL for details.
fetchmail: OpenSSL reported: error:0A000086:SSL routines::certificate verify failed
fetchmail: server4.com: SSL connection failed.
fetchmail: socket error while fetching from user4@server4.com@server4.com
fetchmail: Query status=2 (SOCKET)
fetchmail: Server certificate verification error: self-signed certificate in certificate chain
fetchmail: Missing trust anchor certificate: /C=US/O=Let's Encrypt/CN=R3
fetchmail: This could mean that the root CA's signing certificate is not in the trusted CA certificate location, or that c_rehash needs to be run on the certificate directory. For details, please see the documentation of --sslcertpath and --sslcertfile in the manual page. See README.SSL for details.
fetchmail: OpenSSL reported: error:0A000086:SSL routines::certificate verify failed
fetchmail: server3.com: SSL connection failed.
fetchmail: socket error while fetching from user3@server3.com@server3.com
fetchmail: Server certificate verification error: self-signed certificate in certificate chain
fetchmail: Missing trust anchor certificate: /C=US/O=Let's Encrypt/CN=R3
fetchmail: This could mean that the root CA's signing certificate is not in the trusted CA certificate location, or that c_rehash needs to be run on the certificate directory. For details, please see the documentation of --sslcertpath and --sslcertfile in the manual page. See README.SSL for details.
fetchmail: OpenSSL reported: error:0A000086:SSL routines::certificate verify failed
fetchmail: server2.com: SSL connection failed.
fetchmail: socket error while fetching from user2@server2.com@server2.com
fetchmail: Query status=2 (SOCKET)
fetchmail: Server certificate verification error: self-signed certificate in certificate chain
fetchmail: Missing trust anchor certificate: /C=US/O=Let's Encrypt/CN=R3
fetchmail: This could mean that the root CA's signing certificate is not in the trusted CA certificate location, or that c_rehash needs to be run on the certificate directory. For details, please see the documentation of --sslcertpath and --sslcertfile in the manual page. See README.SSL for details.
fetchmail: OpenSSL reported: error:0A000086:SSL routines::certificate verify failed
fetchmail: server1.com: SSL connection failed.
fetchmail: socket error while fetching from user1@server1.com@server1.com
fetchmail: Query status=2 (SOCKET)

In principle I should be able to report the exit node somewhere. But I don’t even know how I can determine which exit node is the culprit. Running nyx just shows some of the circuits (guard, middle, exit) but I seem to have no way of associating those circuits with fetchmail’s traffic.

Anyone know how to track which exit node is used for various sessions? I could of course pin an exit node to a domain, then I would know it, but that loses the benefit of random selection.

cross-posted from: https://lemmy.sdf.org/post/22571649

According to 15 U.S.C. 7704 §5(a)(5):

INCLUSION OF IDENTIFIER, OPT-OUT, AND PHYSICAL ADDRESS IN COMMERCIAL ELECTRONIC MAIL.—

(A) It is unlawful for any person to initiate the transmission of any commercial electronic mail message to a protected computer unless the message provides—

(i) clear and conspicuous identification that the message is an advertisement or solicitation;
(ii) clear and conspicuous notice of the opportunity under paragraph (3) to decline to receive further commercial electronic mail messages from the sender; and
(iii) a valid physical postal address of the sender.

When my text-based mail client receives an HTML-only email message, it tries to render the HTML as text. It’s sometimes a jumbled up unreadable heap of garbage because the HTML is malformed and relies on a forgiving/tolerant rendering engine. Even when the HTML is proper and standards compliant, links are not exposed to text rendered. E.g. a msg will say “to unsubscribe and stop receiving emails, update preferences here.”

Where is “here”? That is just raw text. Sure, an advanced user can do a number of things to dig up that link. But I doubt that would pass the legal standard of “clear and conspicuous”.

Anyone have confidence either way whether HTML-only spam is legally actionable on this basis?