Malicious PDF — malware analysis report

Static analysis result for SHA-256 81d7bd297708fc9f…

MALICIOUS

PDF

73.3 KB Created: 2021-09-26 02:58:27 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 99f851bd3e1f1ba71c5c339f2e8df459 SHA-1: d4658e6d43abb3b403b1dfb3658ea2748233a819 SHA-256: 81d7bd297708fc9fcf014aff6f7b969734ddd6bced343ba2ebfb992b3b2d3a56
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The ML classifier and ClamAV detection strongly indicate this PDF is malicious. It contains numerous embedded URLs, many pointing to compromised WordPress sites or disposable hosting, suggesting a link farm designed to redirect users to malicious content. The presence of PDF-specific heuristics like 'PDF_SEO_DISPOSABLE_LINK_FARM' and 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' further supports this. The primary attack pattern involves luring users to external sites, likely for phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9915

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://crewmak.ru/uplcv?utm_term=app+watched+multimedia+browser PDF link annotation
    • http://szyuangang.com/UserFiles/file///zoronagovenadudesukeka.pdfIn PDF document text
    • http://de-ko-gmbh.com/ckfinder/userfiles/files/sivenizo.pdfIn PDF document text
    • http://www.vegagastro.pl/upload/file/misesumiwu.pdfIn PDF document text
    • http://www.psyforyou.nl/upload/fckeditor/file/80495089888.pdfIn PDF document text
    • https://ngaa.org.au/application/third_party/ckfinder/userfiles/files/22837177052.pdfIn PDF document text
    • http://hibertek.com/image/files/20210913_225421.pdfIn PDF document text
    • http://ckm-machinery.com/userfiles/files/17873711687.pdfIn PDF document text
    • http://seed-hongkong.com/uploads/file/13651295084.pdfIn PDF document text
    • http://kanizsakran.hu/userfiles/file/68143467771.pdfIn PDF document text
    • https://www.truesdalepainting.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614951fed2802---xarofepafefajux.pdfIn PDF document text
    • https://www.vconsole.com/ckfinder/files/zirilodasezonifi.pdfIn PDF document text
    • http://freemansphotography.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613062fb300d0---63657105519.pdfIn PDF document text
    • http://computerdoki.hu/user/file/wasuwetavolemopegeg.pdfIn PDF document text
    • http://gennarimaq.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/161462dd673d64---79371386779.pdfIn PDF document text
    • https://portalbime.com/UploadedFiles/New/file/16869548900.pdfIn PDF document text
    • http://espwireless.net/uploads/file/59096782580.pdfIn PDF document text
    • http://fujiya-burbank.com/uploads/files/vokeme.pdfIn PDF document text
    • http://quickfix-poland.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614f3601d50c2---6613179122.pdfIn PDF document text
    • https://tabularasa.lv/sites/tabularasa/uploads/documents/files/befasubisuwumurupebudezet.pdfIn PDF document text
    • https://ons-station.com/editor_upload/file/61409551609.pdfIn PDF document text
    • https://chiuman-hk.com/images/file/73794294785.pdfIn PDF document text
    • http://www.onekaddy.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614f476c41eb6---40645292692.pdfIn PDF document text
    • http://kondicionery-dzerzhinskij.ru/upload_picture/file/metagig.pdfIn PDF document text
    • https://jerseyshorepirates.com/userfiles/files/19072922332.pdfIn PDF document text
    • http://forglass.sk/userfiles/file/2271557146.pdfIn PDF document text
    • https://angkagenap.com/contents/files/pebowedapatuwajelemipa.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_off0000b98f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB98F 17276 bytes
SHA-256: 1d129e5715f48422fc61f90eb4f452e225296e61de992fa2d89cf5b8493ec34f
font_01_sfnt_off0000e574.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE574 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000fd8b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFD8B 10980 bytes
SHA-256: 702ae8e0a980ff3e85c2b88604213b5e1413b61d3c4e21daab983b85b10bdb76

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