Malicious PDF — malware analysis report

Static analysis result for SHA-256 8ae8f15f780cf5ab…

MALICIOUS

PDF

102.2 KB Created: 2021-10-09 09:15:19 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: e305e100c1a498ae77fad60caa7f93ae SHA-1: 9c784d7682606f8122aaffc7bd5f3711265bbbc5 SHA-256: 8ae8f15f780cf5ab9c8a9dfab9287c66e5641291818d09a4fde5d5f64194c6d8
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF file contains numerous embedded URLs, many of which point to compromised CMS upload directories, suggesting a phishing or malicious redirection scheme. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for credential harvesting or malware distribution through these links. No scripts were extracted, and the document body was unreadable, but the link farm and compromised hosting heuristics are sufficient indicators.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9961

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • 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 http://kuryakyn.ru/userfiles/file/24172429777.pdf In PDF document text
    • http://zhizhencn.com/filespath/files/20210914035353.pdfIn PDF document text
    • https://stefandes.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613f554a1cdb0---68784969934.pdfIn PDF document text
    • https://foodsafebox.com/ckfinder/userfiles/files/bitumetarofotevepizimowov.pdfIn PDF document text
    • http://dichvuhangngay.vn/uploads/image/files/xuxadojigaxo.pdfIn PDF document text
    • http://tythb.com/uploadfile/files/fedevenukojovolobiz.pdfIn PDF document text
    • https://aurorabersinar2.com/contents/files/75938282439.pdfIn PDF document text
    • http://come2menorca.com/images/file/11643101650.pdfIn PDF document text
    • http://kelvista.lt/images/files/90478988462.pdfIn PDF document text
    • https://by-express.com/upfiles/editor/files/rigogarolefiruzojusapoz.pdfIn PDF document text
    • https://viadagio.be/userfiles/file/57738180472.pdfIn PDF document text
    • http://mega-gold.com/userfiles/files/35087262955.pdfIn PDF document text
    • http://master-stroi76.ru/userfiles/file/42174249958.pdfIn PDF document text
    • https://at1-turbo-j3t.com/contents/files/tulafigakerotiropasidokon.pdfIn PDF document text
    • http://eng.sut.ac.th/tce/2016/administrator/ckfinder/userfiles/files/kojalimajuna.pdfIn PDF document text
    • https://electrodomesticaruano.com/images/ckfinder/files/danofojudixitinodevuweku.pdfIn PDF document text
    • https://bohemiamaestro.com/webpagebuilder/ckfinder/userfiles/files/85697553990.pdfIn PDF document text
    • https://impactmediaresources.com/userfiles/file/6508949617.pdfIn PDF document text
    • https://xn--49st2et51duvk.com/upload/files/kukifan.pdfIn PDF document text
    • http://gallery4walls.com/upload/editer/file/rarofedabifanazup.pdfIn PDF document text
    • http://colantuono.it/userfiles/files/61311125980.pdfIn PDF document text
    • https://qboardapp.com/wp-content/plugins/super-forms/uploads/php/files/bc4003e7425eb25ed5bbc7ce496ee0dc/pudulosegub.pdfIn PDF document text
    • http://ms-beauty.com/ckfinder/userfiles/files/bubixawumojukibe.pdfIn PDF document text
    • https://www.emmabowman.com/wp-content/plugins/super-forms/uploads/php/files/2aa3cda6b833501eb00e417efd1a8ee4/74610835568.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/1KS0DP0cxss/uplcv?utm_term=good+captions+for+sky+picturesPDF link annotation
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In 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_off00012511.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12511 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00013d23.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13D23 20544 bytes
SHA-256: de3b781c9ad8d50f577fee5c7b1d1c29a878b3c881e534e6ba5724a784c3e8d6
font_02_sfnt_off00017151.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x17151 10912 bytes
SHA-256: 1f13666bfebabdec71e8dfc18210490f6a617bba00128b6c1a3de461b3cc9078