Malicious PDF — malware analysis report

Static analysis result for SHA-256 bcb31f9d0a5d621f…

MALICIOUS

PDF

76.3 KB Created: 2021-09-22 10:32:00 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: a812417d8f393994a51d4a3963e3a84a SHA-1: cba0a17d7cd9446fac8d6fb7d72aa46774c0486c SHA-256: bcb31f9d0a5d621f055cd910e356639543125bc0186f09580ee47bb57a72a3d6
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file containing embedded JavaScript, which is a common technique for executing malicious code. It also contains numerous external URIs, many of which point to compromised websites or disposable hosting, suggesting a link farm designed to redirect users. The ClamAV detection and ML classifier strongly indicate malicious intent, likely related to phishing or malware delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9948

Heuristics 7

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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 https://phase1acoustics.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614aca28a7755---19374014106.pdf In PDF document text
    • http://grandfiltr.com/files/file/11119463068.pdfIn PDF document text
    • https://www.rougeindigo.com/ckfinder/userfiles/files/soremuloxize.pdfIn PDF document text
    • http://w-mill.jp/images/file/sebowatolepejabu.pdfIn PDF document text
    • https://basundharamart.com/userfiles/file/57252032266.pdfIn PDF document text
    • http://cinstech-inspect-survey.com/fckeditor_userfiles/file/87619918901.pdfIn PDF document text
    • http://cardealer-space.com/js/upload/files/73281140918.pdfIn PDF document text
    • http://iccjsc.vn/images/uploads/files/76772181748.pdfIn PDF document text
    • http://bascobrunswick.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/161381c024dc04---73022698788.pdfIn PDF document text
    • http://gwtcs.org/Content/uploads/files/vorebiverubiwolexedera.pdfIn PDF document text
    • http://stihoplet.by/upload/editor/files/96498608017.pdfIn PDF document text
    • http://motolargo.pl/userfiles/file/223949081.pdfIn PDF document text
    • https://ducthai.vn/userfiles/file/wugugopimiwesizeto.pdfIn PDF document text
    • http://www.accessibilite-salle-eau.com/ckfinder/userfiles/files/koxafalojepuw.pdfIn PDF document text
    • http://hebammenglueck.de/ckfinder/userfiles/files/zotisegifo.pdfIn PDF document text
    • http://qboardapp.com/wp-content/plugins/super-forms/uploads/php/files/d04eba1e7a00ddc70bc56cecb9b2e4d4/75007786307.pdfIn PDF document text
    • https://futurefacesmiami.com/uploads/file/68681734325.pdfIn PDF document text
    • https://foundryindia.org/userfiles/file/nuvadupa.pdfIn PDF document text
    • http://boki.hu/editor_up/85875750926.pdfIn PDF document text
    • http://britishcytology.org.uk/ckfinder/userfiles/files/dubasakosiliwe.pdfIn PDF document text
    • http://icbiz.ru/userfiles/file/xufebelaralovesaworuzegur.pdfIn PDF document text
    • https://webvitamin.vn/app/webroot/uploads/files/sotajoniwax.pdfIn PDF document text
    • http://esipro.lu/userfiles/file/sizulofe.pdfIn PDF document text
    • https://independentmusicleague.com/wp-content/plugins/super-forms/uploads/php/files/c04b52160546363054f9b20a7d94f109/83118467955.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/zMnd8XtcwSM/uplcv?utm_term=best+app+for+making+3d+animationPDF 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_off0000c608.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC608 17104 bytes
SHA-256: 2a8a610680a9fc6f9897225cfbd026a8a503ec174db3539b32d555cb5393b7a1
font_01_sfnt_off0000f20f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF20F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010a26.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10A26 11112 bytes
SHA-256: 322412f1df3ce69089ef4ca319575255497dc21c1656656600b207775cac322c

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