Malicious PDF — malware analysis report

Static analysis result for SHA-256 9128d50e21ac9a03…

MALICIOUS

PDF

68.8 KB Created: 2021-10-01 07:02:54 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: 281d41a87b151493f9e8c728e4ee02b4 SHA-1: 04c0d659926ad6256e0075102d97759983d0e661 SHA-256: 9128d50e21ac9a03d489fd34a629a0a078f16922d7276c64cf2b40a3340b5a4f
166 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was detected as malicious by ClamAV and an ML classifier. It contains numerous external links, with one specifically flagged as a random URL pointing to a PDF file, suggesting a downloader or phishing lure. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic indicates a link farm on disposable hosting, further supporting the malicious intent of redirecting users to potentially harmful sites. No scripts were extracted, but the presence of multiple external links is a strong indicator of malicious activity.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9982

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 to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://hgindustrial.eu/userfiles/files/27977941940.pdf In PDF document text
    • http://vitrine-prof.com/files/59569909172.pdfIn PDF document text
    • http://pc580.cn/upload_fck/file/2021-9-1/20210901223753628152.pdfIn PDF document text
    • http://odpadykj.cz/UserFiles/File/93814581694.pdfIn PDF document text
    • http://ingegnasrl.com/userfiles/files/zivab.pdfIn PDF document text
    • http://www.alwaysflorida.com/wp-content/plugins/formcraft/file-upload/server/content/files/161403d1b6434f---naxomezolazatajivugofu.pdfIn PDF document text
    • http://jimsclub.net/new/board/img_tinfo/file/20210924043255.pdfIn PDF document text
    • http://paradisoseminatrici.it/userfiles/files/milome.pdfIn PDF document text
    • https://uzunlarpeynir.com/dursun/upload/files/22031313180.pdfIn PDF document text
    • http://pop-around.com/file_media/file_image/file/gitabenit.pdfIn PDF document text
    • http://murzilka.biz/images/uploads/file/46207539651.pdfIn PDF document text
    • http://www.juniorcollege.cl/ckfinder/userfiles/files/sovekebifofapewagexaf.pdfIn PDF document text
    • http://julianowka.pl/ckfinder/userfiles/files/43358143013.pdfIn PDF document text
    • https://tidymoney.com/ckfinder/userfiles/files/tokufeb.pdfIn PDF document text
    • http://baraanduliaptti.org/userfiles/file/56210200284.pdfIn PDF document text
    • http://www.otevrenysklep.cz/ckfinder/userfiles/files/13261561512.pdfIn PDF document text
    • http://clinical-pain.com/pds/userfiles/files/52257420934.pdfIn PDF document text
    • http://impex-italia.it/userfiles/files/94170496032.pdfIn PDF document text
    • https://kamarkosong.com/contents/files/97161337555.pdfIn PDF document text
    • http://mh-gartengestaltung.de/userfiles/file/pazasiwodusagozimejoxejo.pdfIn PDF document text
    • http://ambulatorioveterinariocigliano.com/userfiles/files/70059876611.pdfIn PDF document text
    • https://hotelcorona.ro/files/12210626728.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/DOqCt-cVA4I/uplcv?utm_term=app+hack+among+us+androidPDF 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_off0000af25.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xAF25 10856 bytes
SHA-256: 9901066ac7b1e19cf235cec94f7e6bb28dec4eb02cf5c01496d3333c61442611
font_01_sfnt_off0000c7d7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC7D7 15208 bytes
SHA-256: 6e9da76c198dae88276ee8d1bd8b577b576843d8c25b5523c8ddc878fd624023
font_02_sfnt_off0000ed84.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xED84 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1