J-Security Center

Title: Opera Web Browser 5 Warning Dialogue Bypass Vulnerability

Severity: MODERATE

Description:

Opera Web Browser 5.02 (win32) is a free web browser. When an executable file is requested by the user (for example, by clicking on a link to download it), a warning dialogue is displayed asking whether the user wants to save the file to disk or open it. A checkboxed option, "Always ask when downloading files of this type", is checked and grayed over, implying that all future encounters with executable files will cause a similar warning to be displayed. In spite of this, the choice the user makes the first time a file of this sort is encountered dictates the behavior of the browser with respect to all subsequent executable files. If the user chooses "Open file" (which executes it), all executables encountered in the future will be downloaded and run locally without user warning. Although careful scrutiny could reveal that a malicious link is not what it is being represented as, the casual user would expect to be warned when encountering executable material as this is documented browser behavior. This affects executables from all sources.

This can also be accomplished using redirection (ie, the "refresh" meta tag), so a link to a harmful program could be placed in a web page and executed while the user reads the page.

Affected Products:

  • Opera Software Opera Web Browser 5.0.0 2 win32

References:

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