Sandboxie fails to purge Sandbox - ACCESS DENIED error on delete invocation

Hi Carbonyl,

This is a fairly common scenario, and it is usually triggered by AVs holding on to files. 

A few suggestions:
-Try a leader program setting for Chrome https://www.sandboxie.com/ProgramStopSettings#leader
-Add Sandboxie to the AVs exclusions and see if that helps. 

The last option is what you already figured out, a reboot takes care of whatever is holding on the files and allows Sandboxie to empty the contents. 

Regards,

Hi Barb,

Thanks for the fast reply. I very much appreciate the information. Just to be clear, does the frequency of this issue indicate it's fairly benign? It's the first time I've seen it, and it has me quite worried.

To respond to your suggestions:

-At present the sandbox in question already has Chrome as a leader program. The sandbox was configured this way before the issue occurred, and the settings are still configured that way. From what I can tell, no processes are running in the sandbox at all when this error is encountered.

-I believe I had already added Sandboxie to the exclusions list in ESET, but I will verify that once I get home from work to check on that today.

As an additional question: Is there any way to determine what program is holding on to RegHive? It seems to be quite persistent, but I can't find out what program is doing it in this case.

I'd prefer not to have to reboot my computer every time I want to purge the Sandbox!

Thanks very much for your help on this matter. I will also update as I learn more.

Hi Barb,

Thanks for the fast reply. I very much appreciate the information. Just to be clear, does the frequency of this issue indicate it's fairly benign? It's the first time I've seen it, and it has me quite worried.

To respond to your suggestions:

-At present the sandbox in question already has Chrome as a leader program. The sandbox was configured this way before the issue occurred, and the settings are still configured that way. From what I can tell, no processes are running in the sandbox at all when this error is encountered.

-I believe I had already added Sandboxie to the exclusions list in ESET, but I will verify that once I get home from work to check on that today.

As an additional question: Is there any way to determine what program is holding on to RegHive? It seems to be quite persistent, but I can't find out what program is doing it in this case.

I'd prefer not to have to reboot my computer every time I want to purge the Sandbox!

Thanks very much for your help on this matter. I will also update as I learn more.

Hi Carbonyl,

Each situation may be different, but as you saw in your searches, and as covered in my previous response this is a common situation that gets reported. 
If you are worried about an infection, please do scan your computer with your AV , and if needed, get a second opinion, here's a suggestion:
https://www.sophos.com/en-us/products/free-tools.aspx --> Scroll down to find the "Virus removal tool", which will work alongside your existing AV. 

To see what programs are holding on to files, you may perform an online search for third party software, typically they go by "file unlocker". 

I'd also recommend trying a new Sandbox with default settings (as installing a diff version of Sandboxie does not delete your existing sandboxes). 

If all fails, you may also try manually deleting the Sandbox folder instead of restarting your machine (Navigate to C:\Sandbox\....  to find your Sandboxes and right-click delete the affected one) . 

Let us know how things go. 

Regards,

Hi Barb,

Thanks again for your help on this matter.

Unfortunately, the suggested paths did not result in a solution.

I've done a full malware scan, and the results came back negative - No malware detected.

I've added the RegHive files to the exception list in ESET, and that hasn't remedied the issue, either.

When I check what process has the RegHive files open and won't let go of them, the process is "PID 4 - System". Which is either extremely uninformative, or extremely disturbing.

Even more disturbing - This morning when I started my computer from a COLD BOOT, the first thing I did was try to empty the sandbox. Access was denied!

Further update:

It appears that ESET is actually holding on to a specific registry key even after there are no processes running in the Sandbox, and Sandboxie is trying to close it out.

Ekrn.exe persists in holding open the "HKU\Sandbox_(Username)_(Sandboxname)" key, even long after all processes in the sandbox have terminated.

I am also getting this same error just over the last few days  I am running 2 x WIN7 PC's both with ESET and firefox and with Sandboxie 5.30  I can only delete the firefox contents after a clean reboot  Does this present a threat or can I live with it ubtil a solution is found

I just wanted to note that I have reached out to ESET support about this. I've provided them with log files and am awaiting a response.

Carbonyl Stretch said:

I just wanted to note that I have reached out to ESET support about this. I've provided them with log files and am awaiting a response.

 

Ironically, I've also contacted ESET about this as well detailing how ekrn was holding onto said hive / preventing an unmount {effects both Chrome and Palemoon for me}.  Got a response on the 5th.

This is what they sent me per my case: {Sandboxie "Access is Denied", when deleting sandbox contents}

An ESET Technical Support Representative has updated this case with the following information:

Hello,

Thank you for contacting ESET North America Technical Support.

To exclude an application or IP address from protocol filtering from ESET Windows home products, visit: support.eset.com/.../

Thank you for using ESET security products,
ESET Technical Support
North America
------------------------------------------------------------------------------
ESET Knowledgebase | articles | videos | manuals | support
http://support.eset.com/

Needless to say, excluding the Sandboxie processes under web protocol filtering had no effect in mitigating the issue {nor realtime protection exclusions -- though disabling NOD32 realtime protection "completely" does work}.  I'm also waiting per round two going on ~72 hours since that last reply.  Please do keep the thread updated if you find out anything.

To add a bit more, even if the Sandboxie service is forcefully killed and regedit is launched as "SYSTEM" -- that's still not enough to unmount the hive.  {NOD32 still hangs onto it}

-- Best I've managed to do right now is flushing everything with the exception of the hive, manually, as even disabling realtime protection {post incident} the hive file is still not released.

Hi all,

While you wait for the AV team to reply to you, I have some suggestions

Try deleting the Sandbox folder manually via Safe Mode. Then, reboot to normal mode, and if present, remove the ESET template from Sandboxie (Configure -- Software Compatibility --> Uncheck the ESET template) . Re-test the behavior with a new Sandbox (if this fails, or causes other problems, please re-add the template).

Since you mentioned Ekrn.exe , you may want to try blocking that file in the Sandbox and test what happens (it may or may not work, as it it may trigger error messages).

Right-click on your Sandbox
Sandbox settings---> Resource Access ---> File Access --> Blocked access
Add the following entry:
*\ekrn.exe
Ok and Apply
Re-test

Remove the changes if they don't help/cause problems.

Regards,

Good morning, I have the same problem.
I can not delete the sandbox since the "RegHive" file remains in use after closing all processes.
Do you know if it will take a long time to solve this problem?
I use this application a lot and with this failure it is not operative.

Thank you

Barb@Sophos -- unfortunately the suggested changes did not help.  (removal of ESET from software compatibility, and attempted blocking of ekrn through Sandboxie settings)

-- Lucas, are you also using NOD32 as your AV solution?

So far all responses that I have gotten from ESET have not been promising (getting the runaround), as they have not acknowledged a problem nor the intent to fix said problem.

Disabling components within NOD32 selectively, such as shutting off HIPS or ransomware protection doesn't help ... only complete disabling of NOD32's realtime protection seems to resolve the issue.  Short term, if you rely heavily on Sandboxie I would suggest that you temporarily swap AntiVirus Software.  Of course, you should also open a support ticket with ESET support, so that they see that this impacts many people and it gets escalated.  (I've also tried calling them, though yes the more they hear of this the better -- given it's something they pretty recently broke)

For the record, I went back over to Avira while waiting.  {as I'd happened to still have an active license}  Avira is working just fine with Sandbox deletion.

Same problem here. I think it started with one of the last two Eset module updates on 18.06.2019 or 25.06.2019.

I don't like Avira because of their aggressive marketing. Kaspersky is not compatible with Sandboxie and Bitdefender has a bad performance and no expert options.

EDIT: Did you restart your system after you disabled Eset compatibility in Sandboxie? It seems to work for me.

EDIT 2: After two days of testing with Eset compatibility disabled, I actually can't reproduce the problem anymore.

I tested it with Firefox 68.0 x64, Internet Explorer 11, the old Palemoon 26.5 x86 with downloaded and moved files and PDF read in the browser and even after Windows 7 x64 hibernation.

Maybe the solution only works with Sandboxie 5.28 on Windows 7 x64.

I will post it if the problem should occur again.

EDIT 3: It occurred for all sandboxes in use when I updated a software outside of Sandboxie (the installer uninstalls the old version first). :-|

EDIT 4: I tested it again with Eset compatibility enabled and then it practically always happens. With compatibility disabled it happens much less.