Malicious PDF — malware analysis report

Static analysis result for SHA-256 39e73d26d3227869…

MALICIOUS

PDF

83.0 KB Created: 2021-09-13 22:08:11 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 8f2226cabdba0b49181cde2e283687e4 SHA-1: eebea2e8cddc21a9b81489c51e3b24f99ef77f3d SHA-256: 39e73d26d3227869e54a6ce39bbf6128707d00ef7940c5e0c7f232c7bd99039e
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The file is identified as malicious by ClamAV and an ML classifier, with heuristics indicating it functions as a link farm. Multiple URLs point to potentially compromised or disposable hosting, suggesting an attempt to redirect users to malicious content. The presence of PDF-specific heuristics like 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' and 'PDF_SEO_DISPOSABLE_LINK_FARM' strongly supports this attack pattern.

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://krisoc.ru/uplcv?utm_term=mac+chrome+downloads+shortcut PDF link annotation
    • http://yokosohk.com/files/fckfiles/file/14147796874.pdfIn PDF document text
    • https://www.sahabatkeluargahomecare.com/wp-content/plugins/formcraft/file-upload/server/content/files/16134bd1cc83b7---nozumujotipamepurupolinob.pdfIn PDF document text
    • http://riversedgefm.com/files/file/dumegavivoxamiluw.pdfIn PDF document text
    • http://michelesherrinlaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/gakom.pdfIn PDF document text
    • http://belean.pl/userfiles/file/50016505826.pdfIn PDF document text
    • http://fernandopelosini.it/userfiles/files/83582810800.pdfIn PDF document text
    • https://ipic.vn/userfiles/file/57802960277.pdfIn PDF document text
    • https://clinicaabrahaoosta.com.br/ckfinder/userfiles/files/84014474436.pdfIn PDF document text
    • http://mgtofubbq.com/uploads/files/91207273763.pdfIn PDF document text
    • https://pagodatalk.com/_UploadFile/Images/file/wefivimobobokerotite.pdfIn PDF document text
    • http://nuocmambason.com/upload/fckimagesfile/36c33e31f26f3257695ffe71e753fddd.pdfIn PDF document text
    • https://www.sexualaufklaerung-schule.ch/ck/ckfinder/userfiles/files/35354333438.pdfIn PDF document text
    • http://igigeothermal.jp/userfiles/file/sonozexodoturofusimox.pdfIn PDF document text
    • https://laatjehuisweerstralen.nl/upload/file/94858678976.pdfIn PDF document text
    • https://calienglish.com/ckfinder/images_store/files/penanegulo.pdfIn PDF document text
    • https://siangyun.com/upfiles/editor/files/zezasizuvemujogazabe.pdfIn PDF document text
    • https://tectrongim.com/uploads/files/webixaniwuzixolabotupowa.pdfIn PDF document text
    • http://www.appsolutely.sg/wp-content/plugins/formcraft/file-upload/server/content/files/16130dd0b2eb75---modozal.pdfIn PDF document text
    • https://aparcaderoshaddaichile.cl/uploads/images/files/ruvoxowine.pdfIn PDF document text
    • http://paintingservicesonline.ca/wp-content/plugins/formcraft/file-upload/server/content/files/161389733eb9f3---nuvinexezi.pdfIn PDF document text
    • https://holycrosshealthcare.com/userfiles/files/tiwaruzebobedabojiter.pdfIn PDF document text
    • http://ckm-machinery.com/userfiles/files/60844148379.pdfIn PDF document text
    • http://stoka-saarlouis.de/userfiles/file/nasewijibogi.pdfIn PDF document text
    • http://hotdeals24x7.com/ci/userfiles/files/moxovijux.pdfIn PDF document text
    • http://reklamaopole.pl/userfiles/file/74922766071.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_off0000dead.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDEAD 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f6bf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF6BF 18196 bytes
SHA-256: 109dce2b0e3f4d0a19a2055998132e3a830dcb49a657354d8d8ed2110a5eacf9
font_02_sfnt_off0001258d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1258D 10720 bytes
SHA-256: 057f6db5d32ac1393d70fccc34f63023e3f2f6bf5dc189ee3762e42981de8894

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