Microsoft IIS 4.0 and 5.0 with the IISADMPWD virtual directory installed allows a remote attacker to cause a denial of service via a malformed request to the inetinfo.exe program, aka the "Undelimited .HTR Request" vulnerability.

The shtml.exe program in the FrontPage extensions package of IIS 4.0 and 5.0 allows remote attackers to determine the physical path of HTML, HTM, ASP, and SHTML files by requesting a file that does not exist, which generates an error message that reveals the path.

IIS 4.0 and 5.0 allows remote attackers to cause a denial of service by sending many URLs with a large number of escaped characters, aka the "Myriad Escaped Characters" Vulnerability.

IIS 4.0 and 5.0 does not properly perform ISAPI extension processing if a virtual directory is mapped to a UNC share, which allows remote attackers to read the source code of ASP and other files, aka the "Virtualized UNC Share" vulnerability.

IIS 4.0 allows a remote attacker to obtain the real pathname of the document root by requesting non-existent files with .ida or .idq extensions.

In IIS, an attacker could determine a real path using a request for a non-existent URL that would be interpreted by Perl (perl.exe).