Malicious PDF — malware analysis report

Static analysis result for SHA-256 1591414fcbae8461…

MALICIOUS

PDF

83.6 KB Created: 2021-09-12 14:47:40 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: d05801eb1f6a47d1df8304e139d14bfe SHA-1: 58343496390603bcdbc94db5e50db45440feb9ab SHA-256: 1591414fcbae84612b9861f0016921b3fc34319b9d03661c2d348e1bc5c1b5f6
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by multiple heuristics, including a critical ClamAV detection and an ML classifier, indicating malicious intent. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic and the numerous extracted URLs suggest the document is part of a link farm designed to manipulate search engine results or distribute further malicious content. While no scripts were explicitly extracted, the nature of the PDF and the link farm activity points towards a phishing or content distribution scheme.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9955

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://china-guolin.com/filespath/files/20210904161208.pdf In PDF document text
    • http://easyreturn.store/userfiles/file/wunevubekavudalejobukoma.pdfIn PDF document text
    • http://kiko168.com/UploadFile/file/20210904160008030.pdfIn PDF document text
    • http://webinaris.training/ckfinder/userfiles/publics/files/wavukatiz.pdfIn PDF document text
    • http://zhfangyuan.com/uploadfiles/files/89996259763.pdfIn PDF document text
    • https://pima-alarms.eu/slicice/file/22339390011.pdfIn PDF document text
    • http://www.niceresidence.net/image/upload/File/85337629231.pdfIn PDF document text
    • https://mimpiindah88.com/contents/files/lobatugasoxasoti.pdfIn PDF document text
    • http://www.awakohchang.com/image/upload/File/ufovolidajuwifaxunun.pdfIn PDF document text
    • http://saludocupacionalpso.com/home/wp-content/plugins/formcraft/file-upload/server/content/files/161323078acfd1---kobug.pdfIn PDF document text
    • https://hiperaktivite.info/userfiles/files/98831329651.pdfIn PDF document text
    • http://boki.hu/editor_up/54845904667.pdfIn PDF document text
    • http://ohadalegistrocbarter.com/ckeditor/uploads/files/66841839624.pdfIn PDF document text
    • http://rustproofingottawa.com/userfiles/file/susasuwelewegim.pdfIn PDF document text
    • http://7seapharmtech.com/Uploadfiles/files/rusoka.pdfIn PDF document text
    • https://merlak.ru/userfiles/file/kobasipote.pdfIn PDF document text
    • http://bowie.abwingsmd.com/uploads/files/17510129500.pdfIn PDF document text
    • http://nobody-films.com/bpms/includes/fckeditor_uploads/userfiles/file/debadakemoxiniv.pdfIn PDF document text
    • http://hz-kontejnery.cz/ckfinder/userfiles/files/kelasikawagotemebamosate.pdfIn PDF document text
    • https://speakingparrot.com/upload/ckfinder/files/jokefosuvividodawuwev.pdfIn PDF document text
    • http://vistobrasil.net/uploads/file/midelarurigivige.pdfIn PDF document text
    • http://abapaposentados.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/161374cf9b08d9---94093949351.pdfIn PDF document text
    • http://antifftech.com/uploadfile/file///2021090614444772.pdfIn PDF document text
    • http://toflight.mobi/attachment/ckeditor/files/73734a52c672831eeca37ef883752c44.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/ngfLrbzwjls/uplcv?utm_term=the+maze+runner+book+pdfPDF 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_off0000debb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDEBB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f6cd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF6CD 19136 bytes
SHA-256: 6d0020670970edd45a11aeed8a93e612b70d285f2b8e47a82bf261214eac9f7f
font_02_sfnt_off000128ec.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x128EC 10712 bytes
SHA-256: 003746242342f099984501124eec980682c02493dca1b8aac663b5c1f2e4e109