Malicious PDF — malware analysis report

Static analysis result for SHA-256 33ea638813035cf4…

MALICIOUS

PDF

81.3 KB Created: 2021-09-19 03:03:02 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 672a91c97aadca11f12a080b2807817c SHA-1: 94ccb8c644c35d79992233b514c26968ccf83509 SHA-256: 33ea638813035cf498ddd8207d73a225e4fd9b3166fec28cf48ab9b456007d72
156 Risk Score

Malware Insights

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

The PDF was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, with numerous embedded URLs pointing to various domains, some of which are hosted on compromised CMS upload storage. The primary purpose appears to be directing users to external sites, likely for phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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 https://astoraccessories.com/uploads/ckfinder/files/xakijuwo.pdf In PDF document text
    • http://antropolog.ru/userfiles/file/padilorajuxujoriv.pdfIn PDF document text
    • https://rm-parketi.si/uploads/2328109043.pdfIn PDF document text
    • http://mariopresto.pl/userfiles/file/bitigawudupuninurujuribop.pdfIn PDF document text
    • http://vicc.huh.hu/UserFiles/File/75812458919.pdfIn PDF document text
    • https://bruceautoservice.com/files/file/romukeka.pdfIn PDF document text
    • https://westhygiene.hu/editor_up/86525861072.pdfIn PDF document text
    • https://artinterior.bg/userfiles/file/wapuloporamikaborevazesax.pdfIn PDF document text
    • https://premiumvipbusiness.com/wp-content/plugins/super-forms/uploads/php/files/97c8048e849d486347f774c898d0dee2/90229849563.pdfIn PDF document text
    • https://kp-bs.ru/upload/files/64495894642.pdfIn PDF document text
    • http://hcwan.com/userfiles/file/49243762924.pdfIn PDF document text
    • http://cedresarquitectura.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613175bc2f9a7---36289482799.pdfIn PDF document text
    • https://kolorubursztynu.kolorubursztynu.pl/web/uploads/files/60217478046.pdfIn PDF document text
    • http://aucontecnologia.com/userfiles/files/rowinelegidilumed.pdfIn PDF document text
    • https://umutfm.com/resimler/files/25414912594.pdfIn PDF document text
    • https://vanchuyenduongsat.vn/upload/files/22780479377.pdfIn PDF document text
    • http://www.kzhep.in.ua/wp-content/plugins/super-forms/uploads/php/files/1ht3dh0snff0lof5kp9b1svct1/44893171633.pdfIn PDF document text
    • https://congthuonghotel.vn/app/webroot/files/images/pages/files/xerinanabezotukopax.pdfIn PDF document text
    • https://beautydiction.com/ckfinder/userfiles/files/38875521631.pdfIn PDF document text
    • https://cornerstonelaw.eu/userfiles/file/24497075586.pdfIn PDF document text
    • https://at1-turbo-j3t.com/contents/files/27627458948.pdfIn PDF document text
    • http://dges.in/userfiles/file/zuganatok.pdfIn PDF document text
    • http://abbeloosschinkels.be/userfiles/file/gubabeniduxolotevugisi.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/A3Ryygt5BCM/uplcv?utm_term=miui+stock+appsPDF 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_off0000d8bf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD8BF 10172 bytes
SHA-256: 9397833198652b8a47f0bb5161c0449bc957a6a7a1bb722025dcba0a7f9e50db
font_01_sfnt_off0000efbe.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEFBE 18428 bytes
SHA-256: 383ed1b52334d4788a2d0bd067016b7a0b92ae60d1e7df386831dc38d5030060
font_02_sfnt_off00011fa0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11FA0 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1