Malicious PDF — malware analysis report

Static analysis result for SHA-256 8c91e743ee0ff41e…

MALICIOUS

PDF

70.1 KB Created: 2021-10-01 00:57:17 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 397ac2b354bf9ac7352200adab1e8d1e SHA-1: d8034b2fee17b2e0980f17687f17398a67f4d4e0 SHA-256: 8c91e743ee0ff41e03fe7c59a03546e26b89a2ce2827200a827d66bf2a19ee09
156 Risk Score

Malware Insights

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

The PDF was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, with many URLs pointing to compromised WordPress upload directories and disposable hosting. The document body is unreadable, suggesting it is not intended for human consumption but rather to host these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9965

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 http://songhandiban.com/uploadfile/file/2021091209234573499.pdf In PDF document text
    • https://stw-nowogard.pl/download/file/midasir.pdfIn PDF document text
    • http://fnathservices.com/upload/file/zavenaxasu.pdfIn PDF document text
    • http://www.adanakursmerkezi.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614f2d24c9028---fapovawuxizefotuxuti.pdfIn PDF document text
    • http://www.skupp.pl/wp-content/plugins/formcraft/file-upload/server/content/files/161489db58d28a---41609336052.pdfIn PDF document text
    • http://tmkb.org.tr/ckfinder/userfiles/files/giwanusewixova.pdfIn PDF document text
    • http://espaciocultivarte.com/ckfinder/userfiles/files/63254030873.pdfIn PDF document text
    • https://uslugiinzynierskie.com/eurostyl/photos/file/24785693868.pdfIn PDF document text
    • https://basisnomor.com/contents/files/kigojiw.pdfIn PDF document text
    • http://stolizstekla.ru/userfiles/file/zosebozitaxuwi.pdfIn PDF document text
    • http://aeusjtu.pretty-match.com/upload/files/buboluwijebepesamo.pdfIn PDF document text
    • http://babyshelter.net/assets/upload/files/direkop.pdfIn PDF document text
    • http://pogologistics.com/ckfinder/userfiles/files/fekolikudekuxigaxu.pdfIn PDF document text
    • https://dmshospital.com/mm_engg/files/15736281065.pdfIn PDF document text
    • https://ppntassone.it/dati/upload/file/72452382333.pdfIn PDF document text
    • http://tsrmvolontari.it/userfiles/files/gedibimubopopiwef.pdfIn PDF document text
    • http://paletydozahrady.cz/ckfinder/userfiles/files/xuwed.pdfIn PDF document text
    • http://xn--80adpfaaeictf0c6c7i.xn--p1ai/public/file/segizevikuforomiz.pdfIn PDF document text
    • https://agatanorek.com/files/file/71635493922.pdfIn PDF document text
    • http://cgl.lu/userfiles/files/29300209557.pdfIn PDF document text
    • https://www.temtechnologies.fr/ckfinder/userfiles/files/75399328190.pdfIn PDF document text
    • http://kowel.com/ckfinder/userfiles/files/1632179362.pdfIn PDF document text
    • http://phubozena.pl/userfiles/file/47449793501.pdfIn PDF document text
    • https://ehblending.com/wp-content/plugins/super-forms/uploads/php/files/d0f2ae0376049c03437eb9318894ceed/biniwitekekuseberusabavo.pdfIn PDF document text
    • https://massagetheory.ca/wp-content/plugins/super-forms/uploads/php/files/81883fed7df7802bff2c0e8f9be1eef1/8723783679.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/DOqCt-cVA4I/uplcv?utm_term=mystery+dungeon+dx+all+pokemonPDF 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_off0000b17c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB17C 11044 bytes
SHA-256: 0ab0874013888b13ec7a35967d3dd1adda0f48c036c7896c10950e3134d85ff2
font_01_sfnt_off0000cb0d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCB0D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000e31f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE31F 15716 bytes
SHA-256: bb559af40f3dea1eb4024d9ed84403f2ad7bea37e95110b37240649758878f17