Malicious PDF — malware analysis report

Static analysis result for SHA-256 121b967d90c71d84…

MALICIOUS

PDF

77.5 KB Created: 2021-09-09 02:51:23 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-04
MD5: b856b37eb806025af4cfc37b5d34fd2e SHA-1: b9e7ee7c27cd30adb17f4551742082a863c34231 SHA-256: 121b967d90c71d8431717c0102aadc0c6105459663da50245b775d8fc956cf0e
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF document was flagged as malicious by ClamAV and an ML classifier. The file embeds a large number of external links characteristic of an SEO link farm, many hosted on compromised CMS upload directories. Specific URLs and indicators for this sample are listed in the indicators section.

Machine Learning

  • Nyx PDF Classifier malicious score 0.6343

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • External URI info PDF_URI
    PDF contains an external URL action
  • PDF differential parser failed info PDF_DIFFERENTIAL_PARSE_FAILED
    The cross-check parser (pdfminer.six) failed on this file: PDF differential parser failed: PDFSyntaxError. Static heuristics still ran and any of their findings above are valid; only the differential cross-check signal is missing.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL https://krisoc.ru/uplcv?utm_term=graphing+reciprocal+trig+functions PDF link annotation
    • https://peperita.it/writable/public/userfiles/file/49841318158.pdfIn PDF document text
    • https://www.wappa.com.au/siteadmin/ckfinder/userfiles/files/42355435187.pdfIn PDF document text
    • http://greenhere.cn/upload/ckimg/files/202109081638436527.pdfIn PDF document text
    • http://cowmoo.org/ckfinder/userfiles/files/vafituminaf.pdfIn PDF document text
    • https://prospr.fr/ckfinder/userfiles/files/filudepegoku.pdfIn PDF document text
    • https://nirmalujjwal.com/public/ckfinder/userfiles/files/19900671255.pdfIn PDF document text
    • http://dakdekkersindex.nl/images/uploads/6324184080.pdfIn PDF document text
    • http://internet-trade.eu/UserFiles/file/42832064512.pdfIn PDF document text
    • http://thevisionkharj.com/userfiles/files/rulenifeluwo.pdfIn PDF document text
    • https://badoza.net/userfiles/file/kenafipamojaxajasaxisez.pdfIn PDF document text
    • http://ourpreferred.com/userfiles/files/28997939095.pdfIn PDF document text
    • http://hainfelderteich.at/rewitavolulo.pdfIn PDF document text
    • http://architettotoma.it/userfiles/files/sagatipiterobabuv.pdfIn PDF document text
    • http://buyyoutubecomments.com/ci/userfiles/files/namurefa.pdfIn PDF document text
    • https://riverasphotovideo.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612f2ae45eeda---mosibefenexujiduvekojo.pdfIn PDF document text
    • http://www.ez4parcel.net/upfile/files/2021/09/08/96521316949.pdfIn PDF document text
    • http://shopcloud.cloud/ckfinder/userfiles/files/xakubuk.pdfIn PDF document text
    • http://visualpaint.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613099b680927---gekuwariwuzexig.pdfIn PDF document text
    • http://yuseigachi.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1613739bec060b---23847457458.pdfIn PDF document text
    • https://mimpishiosatu.com/contents/files/82650304743.pdfIn PDF document text
    • http://kondicionery-noginsk.ru/upload_picture/file/9146449564.pdfIn PDF document text
    • http://local-minicab.com/survey/userfiles/files/povikapepepikitategej.pdfIn PDF document text
    • http://dohertylaw.net/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/5064270652.pdfIn PDF document text
    • http://mclarenquartz.in/ci/userfiles/files/banezegolor.pdfIn PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d4d5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD4D5 10900 bytes
SHA-256: 9d384c4e855a46008dc8a373d93d2379b7610f179f57e046435dc2dbce3e0d4c
font_01_sfnt_off0000ee06.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEE06 17776 bytes
SHA-256: 0c8783333c3f7fb931c8f1986be114d3b17083c58115747c98e8942c6c3156c6
font_02_sfnt_off00011c76.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11C76 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1