Malicious PDF — malware analysis report

Static analysis result for SHA-256 b36c741bc1c7a18d…

MALICIOUS

PDF

95.6 KB Created: 2021-07-07 15:29:11 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-08-20
MD5: fe28f47e018036bab6ddc36a12aef083 SHA-1: 0dd8ab5f1137e94e2820ed47a3c8322780352110 SHA-256: b36c741bc1c7a18db268c1bfe33b68473065397d426bb9e2241a43db9b540d56
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains numerous external links, with several pointing to websites that appear to be compromised CMS uploads. The ML classifier and ClamAV detection strongly indicate malicious intent, likely phishing or malware distribution via these links. No scripts were extracted, and the document body was unreadable, so the attack pattern is inferred from the link farm behavior and heuristic findings.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9935

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
  • 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://thestarbusan.net/FileData/ckfinder/files/20210625_F866B350B205C136.pdf In PDF document text
    • http://rusiuojigalvoji.lt/wp-content/plugins/formcraft/file-upload/server/content/files/1609e065052bcb---zurasavurusuwedemitow.pdfIn PDF document text
    • http://www.iqubz.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608e5551145e1---nikedubu.pdfIn PDF document text
    • https://www.oneirishrover.com/wp-content/plugins/super-forms/uploads/php/files/107e205b3cfc1806adcad99df364305a/53884773227.pdfIn PDF document text
    • https://rijst.nu/userfiles/file/wagosebi.pdfIn PDF document text
    • https://stpeterscbs.ca/ckfinder/userfiles/files/94293584157.pdfIn PDF document text
    • http://ucity69.com/clients/861769/File/vugukawozewoxaxa.pdfIn PDF document text
    • http://inspirationallabels.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1608800acf17d6---zedaxasegozovovajosox.pdfIn PDF document text
    • http://ever-pioneer.com/upload/files/xewenunukev.pdfIn PDF document text
    • http://nfc-lampang.com/user_img/files/takota.pdfIn PDF document text
    • https://www.prestigeautobody.com.au/wp-content/plugins/super-forms/uploads/php/files/86b6ec15e8e469d9196b340567df037a/vulokugusef.pdfIn PDF document text
    • https://svetpoznaniyaonline.ru/wp-content/plugins/super-forms/uploads/php/files/b1a554f46b8916a5801734e3af8fc555/napugagixokov.pdfIn PDF document text
    • https://codecs.ro/images/file/gilipe.pdfIn PDF document text
    • http://elisa5888.com/shopadmin/upload/files/31815944581.pdfIn PDF document text
    • http://argentum.com/wp-content/plugins/super-forms/uploads/php/files/e1c8biirho5hpc2aj12sfcujd7/55029760988.pdfIn PDF document text
    • http://bilagroup.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a87567d80de---16724318071.pdfIn PDF document text
    • https://www.waterlooarmsnewforest.co.uk/wp-content/plugins/super-forms/uploads/php/files/e9de52141c747d6b4a2c83bf69334077/6508052460.pdfIn PDF document text
    • https://humanistbeauty.com/wp-content/plugins/super-forms/uploads/php/files/c1p4tk4kbru27m07eruafl731o/tiruxituvi.pdfIn PDF document text
    • http://caribsplash.org/wp-content/plugins/formcraft/file-upload/server/content/files/160d6fdeae7071---merebukonezanasetugevep.pdfIn PDF document text
    • https://leunamgroup.com/wp-content/plugins/super-forms/uploads/php/files/c5835feb14b5bc36afe13587ceb9723c/37662082956.pdfIn PDF document text
    • http://bagiez.com/userfiles/file/8136070422.pdfIn PDF document text
    • https://vibanghanoi.com/uploads/files/zufoxe.pdfIn PDF document text
    • https://midasspa.com/ckfinder/userfiles/files/47215207671.pdfIn PDF document text
    • http://fecoil.com/userfiles/file/67369254478.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/LPIa9PGmDLg/uplcv?utm_term=efficiency+of+a+reversible+heat+engine+is+given+byPDF 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_off00010f20.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10F20 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00012732.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12732 18136 bytes
SHA-256: 7c2e94cfa5f926cf13e15975c3921361be92808be903e05032eec329aed27ce7
font_02_sfnt_off00015738.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x15738 10916 bytes
SHA-256: 4930ef57896f052e6201ee2b4a836b4ffadfaf423fb58b7cad7ffce3cf1c6a25