V
Vanguard
While not anywhere near as nasty as rootkits or using kernel-mode drivers to
hide from APIs, I'd still like to know when Microsoft will begin including
user-friendly tools in the install of Windows (rather than make the user
hunt for the tools) that will expose, list, and detail the content of
alternate data streams for files. Yes, there are 3rd party tools that will
expose them but ADS has been around as long as NTFS because ADS is a feature
of NTFS. When I last asked almost 60 programmers and QA testers who
consider themselves knowledgeable about Windows, the number of expert users
that even heard of ADS could be counted with the free fingers on one hand
while clenching a beer.
So many users haven't a clue what are cookies and they go screaming
"Cookies, Cookies" without a clue as to what they are, that something ELSE
has to create and use them, the browser can be configured to control them,
and that there are plenty of utilities around to manage them. Then came
..sol files for Flash player that were supposedly evil despite the ability to
configure them so they don't get created. Yet these are docile files that
something else has to create and use. Yet there's no noise about ADS and
what can be hidden in there. It wasn't until Ad-Aware SE added detection of
ADS that then some other utilities started including its detection, and most
anti-virus programs never bother to look there and rely almost entirely on
their on-access scanner (because their on-demand scanner doesn't look in the
ADS of files) to catch the content of ADS when it gets read or loaded into
memory to then see if it is bad.
Kaspersky's anti-virus product stores data in the ADS so it can determine if
the file has changed and, if not, it doesn't need to rescan that file which
is how they hid that their scanner is a bit slow, something akin to web
"accelerators" offered by several ISPs that merely don't download all of the
content of graphic images so it looks like surfing is faster. That's about
the only "good" use that I've seen for ADS. Are there any others? And why
is ADS still so well hidden from the user simply due to the lack of
utilities to expose it, like not even indicating in Explorer that ADS is
used on a file, how many alt streams there are, and a means of looking at
them? It's not like ADS is something new.
ADS has been part of NTFS as long as NTFS has been around. Like cookies,
they don't do anything by themselves. Something else has to read them or
load them into memory to execute their content, but with everyone screaming
that cookies are so evil then why hasn't ADS been addressed? Presumably the
"something else" gets detected so it can't use or run the content in the
alternate stream. The only malicious use that I've seen so far is in
consuming disk space without the user having a clue as to why. An innocent
looking 4KB .txt file on the hard drive in an NTFS partition could have a
100GB ADS on it. Ad-Aware will alert on the ADS and TDS-3, as I recall,
will also alert, and there are 3rd party tools to find which files have
alternate data streams, but most users wouldn't even know that they should
be looking because Microsoft has done an excellent job of hiding when a file
has alternate data streams.
Some references:
http://support.microsoft.com/?id=105763
http://snipurl.com/7g73
http://www.ntfs.com/ntfs-multiple.htm
http://support.microsoft.com/?id=105763
http://www.windowsecurity.com/articles/Alternate_Data_Streams.html
Utilities to detect ADS:
http://www.heysoft.de/nt/ntfs-ads.htm
http://www.crucialsecurity.com/downloads.html (crucialADS utility)
http://www.sysinternals.com/ntw2k/source/misc.shtml#streams
Even if Microsoft gets around to adding cookie detection for supposedly
"bad" domains (yeah, like we need to manage a huge list of bad domains
rather than add whitelisting for good ones and force all others to be
per-session cookies by deleting them on exiting IE), I bet they'll still
miss the oh-so evil .sol cookie files left behind by Macromedia's Flash
player (and, no, those files aren't anymore hazardous than .txt cookie
files) despite that the user can configure Flash to not create or save any
..sol files (but, like Microsoft, Macromedia didn't make it obvious to the
user).
If Microsoft is going to waste their time compiling and maintaining a huge
list of "bad" domains so MSAS can detect or block cookies created for those
domains, why not add detection of .sol cookies and of files using ADS?
Exposing the use of ADS would be more important than showing the user that
they have .txt (or .sol) files which already can be managed.
hide from APIs, I'd still like to know when Microsoft will begin including
user-friendly tools in the install of Windows (rather than make the user
hunt for the tools) that will expose, list, and detail the content of
alternate data streams for files. Yes, there are 3rd party tools that will
expose them but ADS has been around as long as NTFS because ADS is a feature
of NTFS. When I last asked almost 60 programmers and QA testers who
consider themselves knowledgeable about Windows, the number of expert users
that even heard of ADS could be counted with the free fingers on one hand
while clenching a beer.
So many users haven't a clue what are cookies and they go screaming
"Cookies, Cookies" without a clue as to what they are, that something ELSE
has to create and use them, the browser can be configured to control them,
and that there are plenty of utilities around to manage them. Then came
..sol files for Flash player that were supposedly evil despite the ability to
configure them so they don't get created. Yet these are docile files that
something else has to create and use. Yet there's no noise about ADS and
what can be hidden in there. It wasn't until Ad-Aware SE added detection of
ADS that then some other utilities started including its detection, and most
anti-virus programs never bother to look there and rely almost entirely on
their on-access scanner (because their on-demand scanner doesn't look in the
ADS of files) to catch the content of ADS when it gets read or loaded into
memory to then see if it is bad.
Kaspersky's anti-virus product stores data in the ADS so it can determine if
the file has changed and, if not, it doesn't need to rescan that file which
is how they hid that their scanner is a bit slow, something akin to web
"accelerators" offered by several ISPs that merely don't download all of the
content of graphic images so it looks like surfing is faster. That's about
the only "good" use that I've seen for ADS. Are there any others? And why
is ADS still so well hidden from the user simply due to the lack of
utilities to expose it, like not even indicating in Explorer that ADS is
used on a file, how many alt streams there are, and a means of looking at
them? It's not like ADS is something new.
ADS has been part of NTFS as long as NTFS has been around. Like cookies,
they don't do anything by themselves. Something else has to read them or
load them into memory to execute their content, but with everyone screaming
that cookies are so evil then why hasn't ADS been addressed? Presumably the
"something else" gets detected so it can't use or run the content in the
alternate stream. The only malicious use that I've seen so far is in
consuming disk space without the user having a clue as to why. An innocent
looking 4KB .txt file on the hard drive in an NTFS partition could have a
100GB ADS on it. Ad-Aware will alert on the ADS and TDS-3, as I recall,
will also alert, and there are 3rd party tools to find which files have
alternate data streams, but most users wouldn't even know that they should
be looking because Microsoft has done an excellent job of hiding when a file
has alternate data streams.
Some references:
http://support.microsoft.com/?id=105763
http://snipurl.com/7g73
http://www.ntfs.com/ntfs-multiple.htm
http://support.microsoft.com/?id=105763
http://www.windowsecurity.com/articles/Alternate_Data_Streams.html
Utilities to detect ADS:
http://www.heysoft.de/nt/ntfs-ads.htm
http://www.crucialsecurity.com/downloads.html (crucialADS utility)
http://www.sysinternals.com/ntw2k/source/misc.shtml#streams
Even if Microsoft gets around to adding cookie detection for supposedly
"bad" domains (yeah, like we need to manage a huge list of bad domains
rather than add whitelisting for good ones and force all others to be
per-session cookies by deleting them on exiting IE), I bet they'll still
miss the oh-so evil .sol cookie files left behind by Macromedia's Flash
player (and, no, those files aren't anymore hazardous than .txt cookie
files) despite that the user can configure Flash to not create or save any
..sol files (but, like Microsoft, Macromedia didn't make it obvious to the
user).
If Microsoft is going to waste their time compiling and maintaining a huge
list of "bad" domains so MSAS can detect or block cookies created for those
domains, why not add detection of .sol cookies and of files using ADS?
Exposing the use of ADS would be more important than showing the user that
they have .txt (or .sol) files which already can be managed.