Executable installers/self-extractors are vulnerable^WEVIL (case 17): Kaspersky Labs utilities

["Stefan Kanthak" <stefan.kanthak () nexgo de>]

Hi @ll,

quite some utilities offered for free by Kaspersky Lab load and execute
rogue/bogus DLLs (UXTheme.dll, HNetCfg.dll, RichEd20.dll, RASAdHlp.dll,
SetupAPI.dll, ClbCatQ.dll, XPSP2Res.dll, CryptNet.dll, OLEAcc.dll etc.)
eventually found in the directory they are started from (the "application
directory").

For software downloaded with a web browser the application directory is
typically the user's "Downloads" directory: see
<https://insights.sei.cmu.edu/cert/2008/09/carpet-bombing-and-directory-poisoning.html>,
<http://blog.acrossecurity.com/2012/02/downloads-folder-binary-planting.html>
and <http://seclists.org/fulldisclosure/2012/Aug/134> for "prior art"
about this well-known and well-documented vulnerability.


If one of the DLLs named above gets planted in the user's "Downloads"
directory per "drive-by download" or "social engineering" this
vulnerability becomes a remote code execution.


Due to the application manifest embedded in some of the executables
which specifies "requireAdministrator" or the installer detection of
Windows' user account control theses installers/self-extractors are
started with administrative privileges ("protected" administrators are
prompted for consent, unprivileged standard users are prompted for an
administrator password); execution of any hijacked DLL results in
an escalation of privilege!


See <http://seclists.org/fulldisclosure/2015/Nov/101> and
<http://seclists.org/fulldisclosure/2015/Dec/86> plus
<http://home.arcor.de/skanthak/sentinel.html> and the still unfinished
<http://home.arcor.de/skanthak/!execute.html> for more details and why
executable installers (and self-extractors too) are bad and should be
dumped.


Kaspersky Lab published a security advisory 2015-12-23
<https://support.kaspersky.com/vulnerability.aspx?el=12430#231215>
after they made updated versions of their utilities available on
<https://support.kaspersky.com/viruses/utility>


stay tuned
Stefan Kanthak

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