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ftp.exe anf tftp.exe buffer overflows

daemon@ATHENA.MIT.EDU (Max)
Fri Feb 28 12:09:17 2003

Date: Thu, 27 Feb 2003 16:43:21 -0800 (PST)
From: Max <rusmir@tula.net>
To: bugtraq@securityfocus.com
Message-ID: <Pine.LNX.4.50.0302271635400.29357-100000@sds.disney.com>
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Hello there,

ftp.exe and tftp.exe both have the same problem with unchecked hostname length.

Description:
    ftp.exe and tftp.exe do not check the length of hostname parameter before
    passing it to gethostbyname(). This makes possible to crash them by providing
    a long enough (~550+ bytes) hostname string.

    According to Microsoft:

    (http://msdn.microsoft.com/library/en-us/winsock/winsock/gethostbyname_2.asp)

    "The gethostbyname function does not check the size of the name parameter
    before passing the buffer. In improperly sized name parameters,
    heap corruption can occur."

Although it is sort of strange behaviour, it is documented.
A good advice for MS developers is to read function description before using it.

Both problems tested on up-to-date W2KPro.

Thanks,

Max.
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