Malicious PDF — malware analysis report

Static analysis result for SHA-256 4041c64eba0916c9…

MALICIOUS

PDF

73.7 KB Created: 2021-09-16 23:10:09 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: 6a7687657cccf63d15e7d15f9ccba397 SHA-1: aa0da36375880b145ffde9f51b9840a241abbd95 SHA-256: 4041c64eba0916c9413360103cbce6f2c23d7f38f2e6eb09ae81f831fa59c196
166 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file is a PDF containing multiple external links, with a high-confidence heuristic identifying a link to an algorithmically generated URL. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or malware distribution. The presence of numerous disposable link farm domains suggests an attempt to obscure the true malicious destination.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://ketchas.ru/uplcv?utm_term=leaves+piano+sheet+pdf PDF link annotation
    • http://kiiga.ru/userfiles/file/36745874874.pdfIn PDF document text
    • http://www.sunarnuricomuisvealisverismerkezi.com/wp-content/plugins/super-forms/uploads/php/files/3u2rfbavaan725a4au2gjblai5/72835613552.pdfIn PDF document text
    • http://ufnk.fr/app/webroot/files/file/lavefadipuxalu.pdfIn PDF document text
    • http://hungthanhauto.com/luutru/files/rofevenamu.pdfIn PDF document text
    • http://upakuika.com/img/file/15676633377.pdfIn PDF document text
    • http://homespakistan.net/magzine/uploadfiles/file/84923237247.pdfIn PDF document text
    • http://bamor.org/userfiles/file/rerofalibinelipowazutip.pdfIn PDF document text
    • http://drxzhang.com/userfiles/file/95440009330.pdfIn PDF document text
    • https://totounited.com/contents/files/rufokazezud.pdfIn PDF document text
    • http://lechioutdoor.com/userfiles/file/jufilebibaxotezukizoruti.pdfIn PDF document text
    • https://thefertilizerequipment.com/d/files/52312230822.pdfIn PDF document text
    • http://beamstraffic.ae/amb/userfiles/file/maxudunasujawerufuwaf.pdfIn PDF document text
    • https://reparation-mobile.net/userfiles/file/nimuxaruzukop.pdfIn PDF document text
    • http://www.findvoters.com/userfiles/file/43315072658.pdfIn PDF document text
    • https://hanoihome.net/img_duhoc/files/zupolerov.pdfIn PDF document text
    • http://es-manzokudou.com/yamituki-n/uploads/files/megolujitejevamesusel.pdfIn PDF document text
    • http://begues.mobi/userfiles/file/49412251622.pdfIn PDF document text
    • http://kavtas.com/images_upload/files/59377022229.pdfIn PDF document text
    • http://peoplefineart.com/assets/202109/files/20210908193501461493.pdfIn PDF document text
    • http://xn--b1adcbbai1bezln.xn--p1ai/content/File/guxifesa.pdfIn PDF document text
    • http://upservice.expert/admin/ckfinder/userfiles/files/41668408206.pdfIn PDF document text
    • https://debden.org/userfiles/file/In PDF document text
    • https://korovin.org/site/img_ufiles/93765551862.pdfIn PDF document text
    • 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_off0000bfc4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBFC4 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000d7db.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD7DB 10472 bytes
SHA-256: e570d25023ab0c32aed028cc8e89bda11f820cf8cbfc914f21953976bf8ca6ef
font_02_sfnt_off0000ef94.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEF94 16476 bytes
SHA-256: 29bc5cb47539fb27e925ce988855f60ef780323c72c699cfc08f26f83e36985c

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