About-face: Apple patches Safari ‘carpet bombing’ bug

In what amounts to a major about-face, Apple has patched the Safari “carpet bombing” vulnerability that led to a Safari-to-Internet Explorer remote code execution combo threat.

After insisting for weeks that the issue is more of an irritant than a security risk, Apple today released Safari v3.1.2 for Windows with a patch warning that saving untrusted files to the Windows desktop may lead to the “execution of arbitrary code.”

From Apple’s advisory:

An issue exists in how the Windows desktop handles executables. Saving an untrusted file to the Windows desktop may trigger the issue, and lead to the execution of arbitrary code. Web browsers are a means by which files may be saved to the desktop. To help mitigate this issue, the Safari browser has been updated to prompt the user prior to saving a download file. Also, the default download location is changed to the user’s Downloads folder on Windows Vista, and to the user’s Documents folder on Windows XP. This issue does not exist on systems running Mac OS X.

The bulletin cites Microsoft’s security advisory on the combo-threat discovered by researcher Aviv Raff.

Safari v3.1.2 for Windows, available for Windows XP and Vista, also fixes at least three additional vulnerabilities that could lead to information disclosure and code execution attacks.

One of the other three bugs also describes a combo threat that goes the other way – Internet Explorer to Safari:

Visiting a malicious website which is in a trusted Internet Explorer zone may lead to the automatic execution of arbitrary code
Description: If a website is in an Internet Explorer 7 zone with the “Launching applications and unsafe files” setting set to “Enable”, or if a website is in the Internet Explorer 6 “Local intranet” or “Trusted sites” zone, Safari will automatically launch executable files that are downloaded from the site. This update addresses the issue by not automatically launching downloaded executable files, and by prompting the user before downloading a file if the “always prompt” setting is enabled.

The IE-to-Safari threat was reported by Will Dormann of CERT/CC .

The browser refresh also plugs a memory corruption issue in WebKit’s handling of JavaScript arrays. “Visiting a maliciously crafted website may lead to an unexpected application termination or arbitrary code execution,” Apple warned.

The fourth vulnerability is an out-of-bounds memory read that may occur in the handling of BMP and GIF images.

Code execution vulnerability found in Firefox 3.0

It’s not all about world records for Firefox 3.0.

Just hours after the official release of the latest refresh of Mozilla’s flagship browser, an unnamed researcher has sold a critical code execution vulnerability that puts millions of Firefox3.0 users at risk of PC takeover attacks.

According to a note from TippingPoint’s Zero Day Initiative (ZDI) , a company that buys exclusive rights to software vulnerability data, the Firefox 3.0 bug also affects earlier versions of Firefox 2.0x.

Technical details are being kept under wraps until Mozilla’s security team ships a patch.

According to ZDI’s alert, it should be considered a high-severity risk:

Successful exploitation of this vulnerability could allow an attacker to execute arbitrary code, permitting the attacker to completely take over the vulnerable process, potentially allowing the machine running the process to be completely controlled by the attacker. TippingPoint researchers continue to see these types of “user-interaction required ” browser-based vulnerabilities - such as clicking on a link in email or inadvertently visiting a malicious web page.

It looks very much like the vulnerability researcher was hoarding this vulnerability and saving it for Firefox 3.0 final release to make the sale.

In the absence of a fix, Firefox users should practice safe browsing habits and avoid clicking on strange links that arrive via e-mail or IM messages.

There are no reports of this issue being exploited but, if you are worried about being at risk of drive-by attacks, consider using a different browser.