There is a current alert for vulnerabilities in these tools, check the end of this post for more.

A minor nuisance of the web is the use of PDF documents to ensure that the information is presented in a particular way that is important to those who still see information as tied to documents. One of its biggest downsides is that quoting and linking to its content is, in the first case very difficult and in the second, impossible.

And if you want to edit one of them its even tougher or expensive. There are some solutions however that can crack open the PDF and make it more tractable. Some are free if you have Linux operating system, some are Windows and cost a little, some are online. There's a great rundown of them at thefreecountry.comSince people keep sending me PDF documents that I had to print, then sign, then scan and return (wasting everything in the process) I spent a few dollars for something that would allow me to fill in PDF forms and drop my signature on the bottom line if needed without all that rigmarole.

Foxit Reader 3.0 for Windows

I bought a copy of this software for about US$30 a few years ago, these days it will cost US$39. Note if you already have version 3.0, you need to upgrade as it has a security hole. Version 2.0 like mine doesn't suffer from the hole, probably because it is not so full of "features"

Foxit Reader is a free PDF document viewer, Foxit Pro lets you edit a PDF document and it has some other virtues

* Small: The reader download is about 4MB compared with Acrobat Reader at 20MB.

* Faster loading without splash screens, etc.

* Annotation tool: draw graphics, highlight text, type text and make notes on a PDF document and then print out or save the annotated document.

* Text converter: You may convert the whole PDF document into a simple text file.

* Claimed higher security and privacy: wont connect to the Internet without users' permission.

Basically it does what it says it does without fuss (2.0 anyway) Now for the free online editor.

PDF Hammer

Upload PDF files via your web browser, perform your edits, and then save the files back to your computer. The online editor allows you to view the pages of your PDF files as you edit them, it lets you:

• Create single files by merging multiple files together.
• Rearrange, reorder and delete the pages from existing PDF files.
• Protect the contents of PDF files with password-based security.
• Make PDF files more useful and usable by setting the document information (metadata) fields, including author, title, subject and keywords.

I found some difficulty with this tool, it did not recognise PDF files created by my Open Office Writer, although other people have no problem opening them with their installed PDF readers, Ok as a last resort or if you have the time to mess about, but I wouldn't depend on it.

Security issues with PDF files.

Adobe Reader and Acrobat contain a buffer overflow vulnerability. Exploit code for this vulnerability is publicly available.

By convincing a user to open a malicious PDF file, an attacker may be able to execute code or cause a vulnerable PDF viewer to crash. The PDF could be emailed as an attachment or hosted on a website.

Apply an update

Check your reader for updates, usuallty from within the software and certainly from their corporate website.

Disable JavaScript in Adobe Reader and Acrobat

Disabling JavaScript may prevent this vulnerability from being exploited. Acrobat JavaScript can be disabled in the General preferences dialog (Edit -> Preferences -> JavaScript and un-check Enable Acrobat JavaScript).

Note that this will not block the vulnerability. Adobe products still may crash when parsing specially crafted PDF documents. Disabling JavaScript will mitigate a common method used to achieve code execution with this vulnerability. Also note that when JavaScript is disabled in Adobe Reader, the software will prompt the user to enable JavaScript when it opens a document that uses the feature. So although JavaScript is a single click away, setting this preference can help mitigate exploits that use JavaScript. Some have reported that they have successfully achieved code execution without the use of JavaScript.

Some vendors ship JavaScript support in a separate package. Removing this package may remove JavaScript support in the Adobe PDF reader.

Prevent Internet Explorer from automatically opening PDF documents

The installer for Adobe Reader and Acrobat configures Internet Explorer to automatically open PDF files without any user interaction. This behavior can be reverted to the safer option of prompting the user by importing the following as a .REG file: get someone who knows what they are doing to do this for you if possible.

Disable the displaying of PDF documents in the web browser

To prevent PDF documents from automatically being opened in a web browser:

1. Open Adobe Acrobat Reader.
2. Open the Edit menu.
3. Choose the preferences option.
4. Choose the Internet section.
5. Un-check the "Display PDF in browser" check box.

Disable Adobe Acrobat Windows Shell integration
Disable the Adobe Acrobat Indexing Service filter

More tasks for an expert

Do not access PDF documents from untrusted sources

Do not open unfamiliar or unexpected PDF documents, particularly those hosted on web sites or delivered as email attachments. Please see Cyber Security Tip ST04-010.

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