Malicious PDF — malware analysis report

Static analysis result for SHA-256 b4a9dcadb011255b…

MALICIOUS

PDF

75.0 KB Created: 2021-09-08 07:23:57 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 31f0345453a07e878a4998af33ffeb54 SHA-1: aaf9d773454e22dd13ee6ec0e3e3ca5f890ec362 SHA-256: b4a9dcadb011255bf9b66c44e3a939d51162cd8747692e3d7a39392fbbdb29b4
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1055.012 Process Injection

The file was detected as malicious by ML classifiers and ClamAV, specifically identified as a phishing trojan. Heuristics indicate it functions as a link farm, with numerous URLs pointing to compromised WordPress sites. These links likely serve as redirects to malicious or phishing content, a common tactic for initial compromise.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9980

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://cspdental.com/wp-content/plugins/super-forms/uploads/php/files/eaf4964467f0607ba92ca9d59f46bacf/vamosibivulelubamoset.pdf In PDF document text
    • https://csom.cz/wp-content/plugins/super-forms/uploads/php/files/71068144b909166e6b8c8c250862c313/38062946749.pdfIn PDF document text
    • http://sromedical.com/file_media/file_image/file/16361566176.pdfIn PDF document text
    • https://dermo.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607a0cb7038c8---gegujafomudegomega.pdfIn PDF document text
    • https://regenerativetherapyforpain.com/wp-content/plugins/super-forms/uploads/php/files/4a5c37096d3cebd6536d2d50b5878b5b/83831752166.pdfIn PDF document text
    • http://cbcom.fr/ressource/site-image/files/tafezimamenamune.pdfIn PDF document text
    • http://zonwering-nederland.com/ckfinder/userfiles/files/48433978150.pdfIn PDF document text
    • http://cbelmira.com/wp-content/plugins/super-forms/uploads/php/files/6ee336cd1fc15a6ef40f6ee276f5427e/81336512934.pdfIn PDF document text
    • https://www.helpagesl.org/wp-content/plugins/formcraft/file-upload/server/content/files/160917ac4acb26---45816035293.pdfIn PDF document text
    • http://elenasteele.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d8bb0b26795---rugarumur.pdfIn PDF document text
    • https://onderdurdu.com/upload/ckfinder/files/kobariduvimebexumevazik.pdfIn PDF document text
    • https://www.cr-sdc.org/wp-content/plugins/super-forms/uploads/php/files/9420ea5a808f38b19993f5fef3d0a662/selofukiwa.pdfIn PDF document text
    • http://locnuocvietmy.com/Images_upload/files/79812315879.pdfIn PDF document text
    • http://aj-logistics.com/stock/userfiles/file/46989050125.pdfIn PDF document text
    • https://wkd-uk.com/wp-content/plugins/super-forms/uploads/php/files/0cf4d6485573da67d4ab6885e1eda7aa/30857680409.pdfIn PDF document text
    • http://technocom.pl/editor/file/61490736608.pdfIn PDF document text
    • https://anjingliar.com/contents/files/karaxodomilotuzupowosak.pdfIn PDF document text
    • http://compie.ru/wp-content/plugins/formcraft/file-upload/server/content/files/160c04ebc68b33---memapasegovuzowifunib.pdfIn PDF document text
    • http://sonarkella.com/userfiles/file/boxilaxabap.pdfIn PDF document text
    • http://drvision.org/wp-content/plugins/formcraft/file-upload/server/content/files/160985ea727176---rowixapolibi.pdfIn PDF document text
    • https://rubyyadav.com/nbloom/fckuploads/file/67205905249.pdfIn PDF document text
    • http://medi-sen.com/files/files/67755841450.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/zMnd8XtcwSM/uplcv?utm_term=us+open+tennis+2019+women%27s+draw+pdfPDF 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_off0000c033.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC033 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000d845.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD845 16896 bytes
SHA-256: 7ab594de789a1ab0d57a4ed35d0b69c33d80c2c58f3832a35f941a1dc58dced0
font_02_sfnt_off0001035b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1035B 11200 bytes
SHA-256: 7bebc92f3fc2bee08b842349319e6681e973d388fe0157751e815873d7b1eef2

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