Malicious PDF — malware analysis report

Static analysis result for SHA-256 8d479af66dccd5f7…

MALICIOUS

PDF

68.4 KB Created: 2021-09-28 10:48:22 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: c30cf8efac31c6698f60ec44bb2c3a59 SHA-1: 40af6491c821eee9e5c8f08e072247c0f2a10674 SHA-256: 8d479af66dccd5f7eca29f8d78a05abdf0c665406bb6b43e3c564e4ea808cdbf
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to external PDF files hosted on various domains. Several heuristics indicate this is a link farm, with some links pointing to compromised CMS upload storage. The ML classifier and ClamAV detection strongly suggest malicious intent, likely related to phishing or malware distribution through these linked documents.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9992

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://biblioteka-belzec.pl/upload/files/78783642368.pdf In PDF document text
    • http://ctyrkolky-gamax.cz/data/dokumenty/64075882010.pdfIn PDF document text
    • http://stalmont.eu/userfiles/file/puxafojaguko.pdfIn PDF document text
    • http://kcpsystem.com/userData/board/file/24267894552.pdfIn PDF document text
    • http://eyela.kr/uploadfile/fckeditor/file/memugodixosevuveruji.pdfIn PDF document text
    • http://tnslib.su/userfiles/files/wolezugufuga.pdfIn PDF document text
    • https://agriplan-rs.com/dados/ckfinder/files/solagawonitopagofamerit.pdfIn PDF document text
    • http://www.alex-vasilkov.ru/images/wisdom/file/64884992239.pdfIn PDF document text
    • https://fiberglasssupplydepot.com/userfiles/file/dorirotobewekuxasufegag.pdfIn PDF document text
    • http://montoaneli.com/ckfinder/files/titegilirovixax.pdfIn PDF document text
    • http://terminsk.by/pics/files/92953603837.pdfIn PDF document text
    • http://xperion.hu/wp-content/plugins/super-forms/uploads/php/files/343fdd526d7a9bf153ef24d214acb304/28216254006.pdfIn PDF document text
    • https://akamercedes.com/images/uploads/files/13499775749.pdfIn PDF document text
    • http://thuexedanang247.com/uploads/image/files/36577311966.pdfIn PDF document text
    • http://www.davidwoodpersonnel.com/wp-content/plugins/formcraft/file-upload/server/content/files/161392670afed2---27691909562.pdfIn PDF document text
    • https://psychotherapie-dr-albrecht.de/wp-content/plugins/formcraft/file-upload/server/content/files/1614b85781e642---59721357895.pdfIn PDF document text
    • https://xn--psg-9lac.hu/files/files/61088511380.pdfIn PDF document text
    • http://evopizza.lt/ckfinder/userfiles/files/12937259622.pdfIn PDF document text
    • http://turatabor.hu/media/sarisawezuzujadaranutovi.pdfIn PDF document text
    • http://dakhoanhanai.com/images/files/29891610822.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/3CAf4wW3hvY/uplcv?utm_term=free+robux+no+offers+2020PDF 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_off0000ac42.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xAC42 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000c454.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC454 16056 bytes
SHA-256: bf146110ccfe516a45eaa65e4d3aa6db4fdf8d00a541d3210a140c61e03bd83e
font_02_sfnt_off0000ed1a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xED1A 10372 bytes
SHA-256: 605ca3a5dbb9686399c35236accd1e4d236a4fac8b5a8b09def97dc272affed2