Danish security research company Secunia has reported that Adobe has been offering an insecure outdated version of Acrobat Reader from their website. When the user installs the Acrobat Reader from Adobe.com, the version installed is an old one which has several vulnerabilities.
But Adobe claims that the software is automatically updated after installation. Adobe explains that once Adobe Reader 9.1.0 is installed, the Adobe Updater technology will subsequently offer the Adobe Reader 9.1.1 and 9.1.2 patches. Adobe Updater will check for updates immediately on first launch. Thereafter, Adobe Updater checks for updates every seven days from that first launch.
According to Secunia, the time taken to download and install updates is critical.