Malicious PDF — malware analysis report

Static analysis result for SHA-256 f831dca3a8534765…

MALICIOUS

PDF

84.3 KB Created: 2021-09-15 17:49:45 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: a51b5ea53b47ab0baf2dade7be58e33d SHA-1: 8bcaf95743b45b8025aade69e955141759b2c840 SHA-256: f831dca3a85347650d4edbb4e974ea4cfd384994d445f2c36a4e9b68737f28d0
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file is identified as a malicious PDF by multiple heuristics and an ML classifier, with ClamAV detecting it as a phishing trojan. It contains numerous external URLs, many pointing to compromised CMS upload directories or disposable hosting, suggesting a link farm or phishing lure. The PDF's structure and embedded URLs indicate an attempt to redirect users to malicious sites, likely for credential harvesting or further malware delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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://allytemp.ru/uplcv?utm_term=short+vowel+sound+of+u PDF link annotation
    • http://robwalker.net/fckupload/file/nidopezekapowijara.pdfIn PDF document text
    • http://commsoft.nu/demo/ktb/wsmbilder/files/9800789120.pdfIn PDF document text
    • http://www.patricktennis.nl/wp-content/plugins/formcraft/file-upload/server/content/files/16139132646f29---94871194577.pdfIn PDF document text
    • https://vicareyou.com/userfiles/file/36272679913.pdfIn PDF document text
    • https://giorgiosantinelli.it/file/jifamatuj.pdfIn PDF document text
    • http://wildzipper.com/clients/wildzipper/userfiles/file/13148520989.pdfIn PDF document text
    • http://fujavietnam.com/images/Download/26503578367.pdfIn PDF document text
    • https://mundolibre.cl/uploads/userfiles/files/dudaj.pdfIn PDF document text
    • https://myphambambi.com/webroot/img/files/gotufod.pdfIn PDF document text
    • http://tksvolga.ru/userfiles/file/42247442271.pdfIn PDF document text
    • http://peaceinsrilanka.lk/ckfinder/userfiles/files/45093465657.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/16138218e21de8---mimidipoloraf.pdfIn PDF document text
    • https://mfdesign.hu/files/file/pivokofowitiraliredeliji.pdfIn PDF document text
    • http://fabrikando.com/cmsimple/images/file/74724974998.pdfIn PDF document text
    • https://bettenbaehren.de/wp-content/plugins/formcraft/file-upload/server/content/files/1613c302ec768c---9755780468.pdfIn PDF document text
    • https://www.frontiermyanmar.com/sites/all/libraries/ckfinder/userfiles/files/bivuduzuvi.pdfIn PDF document text
    • http://www.sparkprototypes.com/wp-content/plugins/formcraft/file-upload/server/content/files/16138590138868---gexabojubivuro.pdfIn PDF document text
    • http://rent2day.ca/ci2/userfiles/files/vufavur.pdfIn PDF document text
    • http://tauroconsulting.pl/userfiles/file/53011846427.pdfIn PDF document text
    • http://ck-buhgalter.ru/userfiles/file/dixub.pdfIn PDF document text
    • http://oroblupiscine.it/userfiles/files/ninijarenidoxubidufasa.pdfIn PDF document text
    • http://osmed.cz/app/webroot/files/files/53774714544.pdfIn PDF document text
    • http://maginsaatmetal.com/resimlerfiles/zetuwi.pdfIn PDF document text
    • http://grupopiscis.com/upload/files/fuxisexedegume.pdfIn PDF document text
    • http://kup-vino.cz/web/ckfinder/userfiles/files/wiloravopamuwaxikude.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_off0000df2c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDF2C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f743.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF743 10524 bytes
SHA-256: d38bda21ea799794cc3313ae16d9e8dad170132b1195b4a8d21d1bd3b2c4017f
font_02_sfnt_off00010f3d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10F3D 20372 bytes
SHA-256: 79e6eb7e5ab9c29f572b7b405913bcd9f09843d913dfeb95ebc6e86f6db3880e

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