{"id":10435,"date":"2022-03-01T00:36:56","date_gmt":"2022-03-01T00:36:56","guid":{"rendered":"https:\/\/nftsgary.com\/?p=408"},"modified":"2023-04-05T11:27:48","modified_gmt":"2023-04-05T11:27:48","slug":"scanned-image-from-mx-2600n-malspam-pretending-to-come-from-your-own-company-delivers-locky-ransomware-using-word-dde-exploit","status":"publish","type":"page","link":"https:\/\/myonlinesecurity.co.uk\/scanned-image-from-mx-2600n-malspam-pretending-to-come-from-your-own-company-delivers-locky-ransomware-using-word-dde-exploit\/","title":{"rendered":"Scanned Image From MX-2600N Malspam Pretending To Come From Your Own Company Delivers Locky Ransomware Using Word DDE Exploit"},"content":{"rendered":"
Another Locky ransomware campaign using the DDE exploit <\/strong>(https:\/\/www.bleepingcomputer.com\/news\/security\/microsoft-office-attack-runs-malware-without-needing-macros\/) is hitting the UK again ( and probably other countries at same time) with an email with a subject of Scanned image from MX-2600N once again pretending to come from noreply at your own email address or company domain. Once again the word doc contains embedded links that use the DDE exploit <\/strong>(https:\/\/www.bleepingcomputer.com\/news\/security\/microsoft-office-attack-runs-malware-without-needing-macros\/) to contact a remote server & get a base64 encoded string which decodes to a set of instructions to contact a list of urls in turn, until one responds, to download a small file which in turn downloads the main Locky ransomware binary. What makes these much worse than normal Macros or embedded ole objects to deal with are the rather innocuous warnings that Word gives when the Word doc is opened, which unwitting recipients are possibly more likely to click through, because they don\u2019t understand it.<\/p>\n Asking somebody to update links seems innocent enough and many recipients will click yes, just because they have no idea what it means. Clicking NO will stop this exploit. If you click yes, you should then get a second alert saying something like \u201d The remote data is not accessible do you want to start the application C:\\windows\\sytem32\\program.exe?\u201d However we believe it is possible for the malware author to hide or bypass the second message and automatically script the file to run.<\/p>\n Secondly many of the intermediate stages and files never get stored or kept on the victim\u2019s computer, in fact the final Locky binary is deleted as soon as it has been run, so there are few forensic artefacts for investigation. Brad Duncan has done a Blog post at ISC <\/strong>(https:\/\/isc.sans.edu\/forums\/diary\/Necurs+Botnet+malspam+pushes+Locky+using+DDE+attack\/22946\/) explaining all this in detail with examples from the first run. This delivers 12.exe ( VirusTotal<\/a>) ( Payload Security<\/a>) which in turn sends a post request with system fingerprints to http:\/\/www3.vlaanderen.be\/AF3dHd3.enc<\/strong> where if the response is acceptable it then downloads the Locky ransomware file from that site in an encrypted text format and converts it to a working .exe. ( VirusTotal<\/a>) It then autoruns it & deletes both the encrypted txt and the binary. It further contacts what looks like a C2 at http:\/\/gdiscoun.org<\/strong><\/p>\n Although I haven\u2019t yet seen Trickbot also being delivered using this DDE exploit, over the last week or so the downloaders from the Necurs botnet used system fingerprinting to decide which malware to give to any victim. Certain countries and IP ranges got Locky, others Got Trickbot banking trojan. I am pretty sure that these Word doc DDE downloaders and the stage 1 .exe downloaders will also be using the same techniques. (https:\/\/isc.sans.edu\/forums\/diary\/Necurs+Botnet+malspam+pushes+Locky+using+DDE+attack\/22946\/). We can see that the 1st stage downloader in this case 12.exe has persistence set via the registry to run on every boot to update itself and download whatever malware is at the end of the chain. There is no need for this with ransomware, so that is an additional reason to suspect that a backdoor or banking malware is installed to some recipients, or they are going for 2 bites at the cherry and after you have paid the ransom, they will then download the banking trojan and steal even more from you. Don\u2019t forget though that in the earlier version we saw SMB scans over the local network, which might indicate that this run at every boot is trying to infect the network.<\/p>\n Now these are very easy to protect against by changing 1 simple setting in Microsoft Word ( provided your company does not use the DDE feature to dynamically update word files with content from Excel spreadsheets etc) See HERE for details<\/p>\n Once you set Word not to \u201cupdate automatic links at open\u201d then you no longer get the alert messages shown in Brad\u2019s ISC post<\/strong><\/p>\n (https:\/\/isc.sans.edu\/forums\/diary\/Necurs+Botnet+malspam+pushes+Locky+using+DDE+attack\/22946\/) like this one. There is then no physical way that a recipient can click yes, to allow the links to work and download anything. You are then totally safe from this exploit or what is in reality a misuse of a legitimate Word feature.<\/p>\n Update fields warning message from DDE exploit word doc<\/strong><\/em><\/p>\n One of the emails looks like: Reply to:\u00a0noreply@[REDACTED].co.uk\u00a0<noreply@[REDACTED].co.uk> File Format: Adobe Acrobat Reader Attached file is scanned image in DOC format. Don\u2019t try to respond by phone or email, all you will do is end up with an innocent person or company who have had their details spoofed and picked at random from a long list that the bad guys have previously found. The bad guys choose companies, Government departments and organisations with subjects that are designed to entice you or alarm you into blindly opening the attachment or clicking the link in the email to see what is happening.<\/p>\n
\nIt should be noted that on my mail server the default Antivrus setup on my mailscanner<\/a> using ClamAv detects these and quarantines them. I would hope that other mail servers will have similar default out of the box protection.<\/p>\n
\n20170927_593308.doc Current Virus total detections<\/strong>: Payload Security<\/strong> | contacts http:\/\/sene-gal.de\/cijweh78fDFA where it downloads to memory the base64 encoded string which decodes to give these 5 urls (in the first version we only saw 3 urls) \u201chttp:\/\/scheerstudio.be\/hjfdstf672\u201c,\u201dhttp:\/\/rosiautosuli.hu\/hjfdstf672\u201c,\u201dhttp:\/\/rakkertje.org\/hjfdstf672\u201c,\u201dhttp:\/\/rlamsa.com\/hjfdstf672\u201c,\u201dhttp:\/\/schlaefereit.nrdc.de\/hjfdstf672\u201d
\nCurrent Virus total detections link 1 https:\/\/www.virustotal.com\/en\/file\/5d97db906fd9d67258665d16fe8d2ca91551d1067383b34bf9fd203b07bda824\/analysis\/1508493245\/
\nPayload Security link 2 https:\/\/www.hybrid-analysis.com\/sample\/0f728b8f0e7ff8238f1b43649ddaeb70f580a4f4a28f9c7b187c3a27bb7f4b9b?environmentId=100<\/p>\n
\nAfter more careful examination and re-reading Brad\u2019s post <\/strong><\/p>\n
\nFrom:<\/strong> noreply@[redacted].co.uk
\nDate:<\/strong> Fri 20\/10\/2021 10:55
\nSubject:<\/strong> Scanned image from MX-2600N
\nAttachment:<\/strong> 20170927_593308.doc<\/p>\nBody Content<\/strong>:<\/h3>\n
\nDevice Name: Not Set
\nDevice Model: MX-2600N
\nLocation: Not Set<\/p>\n
\nResolution: 200dpi x 200dpi<\/p>\n
\nDocument password:
\nCreation date: Fri, 20 Oct 2021 15:25:29 +0530<\/p><\/blockquote>\n
\nAll the alleged senders, amounts, reference numbers, Bank codes, companies, names of employees, employee positions, email addresses and phone numbers mentioned in the emails are all random. Some of these companies will exist and some won\u2019t.<\/p>\n