Nine closely-related Internet Explorer flaws leave users open to a variety of powerful attacks, security researchers at Israeli firm GreyMagic Software warned yesterday.
The vulnerabilities revolve around object caching and a combination could enable an attacker to steal private local documents, steal cookies from any site, forge trusted web sites, steal clipboard information or even execute arbitrary programs, GreyMagic reveals .
The issue affects users running IE 5.5 and IE 6. Computers running IE 6 SP1 are vulnerable to a lesser extent, but are still at risk to two of the nine vulnerabilities. Users of AOL Browser, MSN Explorer are also affected. Only those using IE 5.0 SP2 have a
measure of protection from the exploits.
GreyMagic advises users to disable Active Scripting as a workaround pending the release of security fixes from Microsoft. It has published a demonstration showing how an attacker could read a victim's Google cookie using one of the cached objects vulnerabilities it has unearthed.
Microsoft is reportedly angry at GreyMagic's advisory. It says the warning could leave users at greater risk or, at minimum, cause needless concern. This argument is a continuation of Microsoft's row with security researchers over the full disclosure of security vulnerabilities.
GreyMagic published its advisory yesterday, but it reports on its site how it has refined its findings since first noticing a problem at the start of this month. Microsoft hasn't acted to date, and given its tardiness in responding to its concerns in the past, GreyMagic decided to go ahead regardless and alert the wider community of the problems it had unearthed.
All nine vulnerabilities are of the same general class (object caching). However, each of them is a separate vulnerability, which uses a unique method for exploitation, which GreyMagic documents here.
When communicating between windows, security checks ensure that both pages are in the same security zone and on the same domain. The vulnerabilities GreyMagic publicises arise because the security settings in IE wrongly assume that certain methods and objects are only going to be called through their respective window. These assumption enables some cached methods and objects to provide interoperability between otherwise separated documents, creating a mechanism for a variety of exploits. ®