Questions tagged [pdf]

Portable Document Format (PDF) is an open standard for electronic document exchange maintained by the International Organization for Standardization (ISO). Questions can be about PDF specific malware or protections.

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7
votes
2answers
16k views

How secure a secured PDF really is? [duplicate]

I've googled the internet for answers regarding secured pdf/cracking them and found huge amount of stuff. But most of it is quite old. So could someone confirm the following is still valid in modern ...
0
votes
1answer
165 views

How does DRM enforcement work (across different platforms)? [closed]

I would like to know how Android, Windows, Linux, and OS X deal with DRM (Digital Rights Management) e-pub, pdf, and mp3 files. Basically, if I download a DRM file to my device (perhaps one that has ...
6
votes
1answer
2k views

Bank Has Emailed My Social Security Number

I'm in the middle of getting a mortgage. Just now, my bank sent over an e-mail (sent to my Gmail account) with a bunch of .pdf attachments of documents I'm supposed to sign and return. The first ...
1
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0answers
189 views

Does this pdf file embeds an exploit or malware?

So a friend of mine was sent a phishing attack(Which was tailored for him and he fell for it) which also downloaded this pdf file: hxxps://www.dropbox.com/s/qw9mcw9p3pmc5j5/resume.pdf?dl=0 and he ...
5
votes
1answer
692 views

Verification of a timestamped PDF

I'm kinda new to the process of timestamping files to provide digital integrity. For testing purposes, i use tsa.safecreative.org for PDF files. Now i've signed a couple PDF files and if i open up ...
2
votes
1answer
297 views

Strategy for electronic document (PDF) signatures

I'm treading into the murky waters of electronic document signatures, and I'm having trouble figuring out the right approach to deal with my requirements. I think this should be pretty straightforward,...
-1
votes
2answers
154 views

Need tool to detect malware in several pdfs in Windows environment [closed]

I am looking for a Windows product that could detect malware in several pdfs in Windows environment. I don't want to use Python and I don't want to use Stream Dumpler. I am looking for something ...
0
votes
0answers
73 views

deceptive digital signature?

I am new to cyphering and I try to understand this case : my government sends me so-called "digitally signed" PDFs, as you can see below (text only, after "Thanks"). Although there is a certificate ...
16
votes
2answers
4k views

Effectiveness of flattening a PDF to remove malware

I'm currently looking at ways to prevent malicious PDF files at the network boundary. This will include virus scanning - but there are known limitations to that. I see a common approach is to flatten ...
5
votes
1answer
2k views

PDF file encrypted with my password, does that mean my password is stored in plaintext?

Every month, I receive an encrypted Portable Document Format (PDF) file with my payslip. I can open the file for reading with my password. Without providing my password, I cannot open the file at ...
6
votes
1answer
1k views

Can I redact by converting PDF to TIFF and back?

Background My boss asked me to come up with a way ordinary users can redact information from PDF files using free software. We get a lot of scanned documents and our client requires that sensitive ...
0
votes
1answer
122 views

Does a 'mailto:' hyperlink spoil any preceding email obfuscation efforts in PDF?

Assume there is a PDF file which contains the example@example.com email address as an image (the classic obfuscation method). However, what if this image is made clickable with a hyperlink which ...
4
votes
2answers
7k views

Removing malware from a malicious PDF file [duplicate]

I have analyzed a large PDF using Didier Steven's pdfid tool. I get the following result: Now that I know there is malicious content in the PDF, what can I do to remove it? I would still like to view ...
64
votes
3answers
34k views

What security scheme is used by PDF password encryption, and why is it so weak?

Many PDFs are distributed as encrypted PDFs to lock out some of their functionality (eg printing, writing, copying). However, PDF cracking software is available online, which usually cracks the PDF ...
0
votes
0answers
819 views

What is the format of PDF hash?

When I use a tool like pdf2john.py from John The Ripper on an encrypted PDF, it gives me an output like: `testing1.pdf:$pdf$2*3*128*-1028*1*16*3ba51ab2b4f9210274ccb07b8da9ec59*32*...
-1
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2answers
2k views

Why is PDF still safe?

Something I was wondering about after reading Didier Stevens Labs 2008 post: There are endless ways described how to put potential malicious content into a pdf file, while making it impossible for ...
4
votes
2answers
2k views

How to remove meta and sensitive data from PDF file?

I've some PDF files generated from different sources (such as web-browser, Photoshop, etc.) on Unix. How do I make sure PDF doesn't contain any sensitive information such as IP address, OS, user name,...
2
votes
2answers
13k views

Determine Security Of A PDF File [closed]

How do I find the exact encryption on a PDF file? I can't seem to get a direct answer on the net. For example how do I tell if a document is PDF 1.1 - 1.3 (Acrobat 2 - 4), PDF 1.4 - 1.6 (Acrobat 5 - 8)...
1
vote
0answers
461 views

PKCS#7 signed data structure in signed PDF document

Is it mandatory to include PKCS#7 data (OID 1.2.840.113549.1.7.1) octet string into the sequence of PKCS#7 signed data? I mean if you want to sign PDF, you are basically adding PKCS#7 container ...
5
votes
1answer
2k views

Standard to represent digital signature on paper

Users are making a deal using the website. Website generated PDF file (something like contract or report). Users perform digital signing of this file (analogous to hand-written signature on paper ...
16
votes
1answer
30k views

How can I extract the hash inside an encrypted PDF file?

As long as I know, the encrypted PDF files don't store the decryption password within them, but a hash asociated to this password. When auditing security, a good attemp to break PDF files passwords ...
0
votes
3answers
232 views

Security concerns of downloading websites contents

I recently started using Firefox for Android and saw I can download pages as PDF and near every image or video for any site and I'm using that quite a lot so what is the risk of downloading such ...
1
vote
1answer
2k views

Server-based PDF Signing using HSM

I have some question about server side pdf signing using network-attached hardware security module. my first question is: what is PDF Signing Certificate? Certificates are public keys, how a ...
2
votes
2answers
837 views

Convert PDF to plain text, remove malware?

Take a PDF, copy all, paste it into a .rtf document in textedit, --> make plain text. will this remove/nullify any malware from/in the pdf? In other words, if I open the PDF on one machine and convert ...
5
votes
3answers
6k views

Detected virus in pdf - should I be worried (CVE-2014-8449)?

I downloaded a pdf earlier, and I was trying to send it to my friend, but gmail said that it detected a virus. So I ran it through virustotal.com and only 1 out of 56 scanners came up with a virus - ...
1
vote
1answer
837 views

ClamAV detected CVE-2014-8449 in some PDFs. How do I know if it's a real problem?

We run clamav on all our user-uploaded files. It's currently giving this message for several PDFs: <filename...>: Pdf.Exploit.CVE_2014_8449 FOUND Looking at the CVE, it's for a integer ...
5
votes
4answers
1k views

Remove pdf malware by re-printing to new pdf or text extract?

Consider you have a suspicious pdf file that might contain malware. Would it be sufficient to either: open the pdf file in a virtual environment and let the pdf viewer or pdf-creator program "print-...
22
votes
4answers
6k views

Detecting and preventing 'phone home' behavior in PDF files

I have received several PDF documents via email from someone I do not trust. I need to read the documents and respond to them. They are not encrypted. I want to make sure the documents are ...
16
votes
1answer
1k views

Malicious PDF Analysis

I have been analyzing a PDF I suspect to contain malicious content. For the most part, I've always trusted automated tools to determine if a PDF was safe to open. However, my eyes have been opened to ...
10
votes
1answer
5k views

What are the security risks associated with PDF files?

What are the security risks associated with PDF files? There is, of course, the general risk associated with any type of file: that whatever application is used to read it will have a bug that can be ...
-1
votes
2answers
25k views

how to embed exe file to pdf? [closed]

Im trying to embed exe file to pdf for case study. I try using metasploit exploits for this but i can only embed shellcodes with this method. I know there is a way to embed exe file but i cant find ...
3
votes
1answer
2k views

How strong is PDF security/encryption?

I want to securely convey a PDF document containing sensitive information from my system to another system. The latter is operated by a different person, whom I trust. However, this person does not ...
8
votes
1answer
424 views

Security of PDF reader software

Are there any studies regarding the security of PDF viewer software from different vendors? I try to find the most secure reader.
68
votes
3answers
232k views

Can a PDF file contain a virus?

Could a PDF file contain any type of malware?
47
votes
11answers
54k views

How to safely view a malicious PDF?

I have a PDF with important information that may contain malware. What would be the best way to view it?
42
votes
5answers
59k views

How to scan a PDF for malware? [closed]

Can anyone suggest an automated tool to scan a PDF file to determine whether it might contain malware or other "bad stuff"? Or, alternatively, assigns a risk level to the PDF? I would prefer a free ...

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