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Vulnerability of Microsoft HTML Help: buffer overflow

Synthesis of the vulnerability 

An attacker can invite the victim to open a malicious CHM file with Microsoft HTML Help, in order to execute code.
Vulnerable systems: Windows 2000, Windows 2003, Windows 2008 R0, Windows 2008 R2, Windows 7, Windows Vista, Windows XP.
Severity of this threat: 2/4.
Creation date: 13/04/2011.
Références of this weakness: BID-47330, VIGILANCE-VUL-10562.

Description of the vulnerability 

Files with a CHM extension are compiled help files for Windows, which are opened with Microsoft HTML Help.

Data are compressed in blocks. Microsoft HTML Help thus uncompresses each block before using it. However, if the size of a block is too large, a buffer overflow occurs.

An attacker can therefore invite the victim to open a malicious CHM file with Microsoft HTML Help, in order to execute code.
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This computer weakness bulletin impacts software or systems such as Windows 2000, Windows 2003, Windows 2008 R0, Windows 2008 R2, Windows 7, Windows Vista, Windows XP.

Our Vigil@nce team determined that the severity of this computer threat announce is medium.

The trust level is of type confirmed by the editor, with an origin of document.

A proof of concept or an attack tool is available, so your teams have to process this alert. An attacker with a technician ability can exploit this threat announce.

Solutions for this threat 

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