Malicious PDF — malware analysis report

Static analysis result for SHA-256 3bd12558ecf12f5c…

MALICIOUS

PDF

82.7 KB Created: 2021-08-17 14:27:46 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-20
MD5: bf4a31bbe911a73c37d2b3f21af6ad2c SHA-1: bd99b4accdb3b70956596392f76426ddc310e6fe SHA-256: 3bd12558ecf12f5c1b0e501b5cfd3df85805b6b2b153cc3042371892f45d697b
156 Risk Score

Malware Insights

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

The sample is a PDF file flagged by ClamAV as Pdf.Phishing.Trojan and by an ML classifier as malicious. It contains numerous external links, many pointing to compromised WordPress sites or disposable hosting, suggesting a link farm designed to redirect users. The presence of multiple PDF_SEO_DISPOSABLE_LINK_FARM and PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM heuristics indicates a tactic to obscure the true destination or leverage compromised infrastructure. The primary attack pattern appears to be luring users to external sites via a phishing or deceptive document.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

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://medvor.ru/uplcv?utm_term=smart+choice+pdf+free+download PDF link annotation
    • http://fractinvest.com/uploads/file/29311571945.pdfIn PDF document text
    • http://chunmianxian.com/upfolder/e/files/20210807172421.pdfIn PDF document text
    • https://europacreativaeuskadi.eu/files/galeria/files/patagibamu.pdfIn PDF document text
    • https://wecareu.net/ckfinder/userfiles/files/dapakuxazif.pdfIn PDF document text
    • http://elateridae.com/images/FCKeditor/file/giwuvuzamebut.pdfIn PDF document text
    • http://www.alwaysflorida.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c05ad24b93a---dexazovuwenitudel.pdfIn PDF document text
    • http://quickfix-poland.com/wp-content/plugins/formcraft/file-upload/server/content/files/16094655f44253---29485480172.pdfIn PDF document text
    • http://www.idenet.net/wp-content/plugins/formcraft/file-upload/server/content/files/160ce12e52668f---votuzapesilobat.pdfIn PDF document text
    • https://profipreklady.cz/www/ckfinder/userfiles/files/7909891614.pdfIn PDF document text
    • http://brilsports.ro/userfiles/file///55982030622.pdfIn PDF document text
    • http://orosweb.hu/ckfinder/userfiles/files/17699446857.pdfIn PDF document text
    • https://www.wappa.com.au/siteadmin/ckfinder/userfiles/files/12361191158.pdfIn PDF document text
    • http://polenes.cl/userfiles/file/53895400499.pdfIn PDF document text
    • http://nakatka.com/files/file/livilidupafafo.pdfIn PDF document text
    • http://tdjl.com/uploadfile/file///2021081001531726.pdfIn PDF document text
    • https://suemsas.com/wp-content/plugins/super-forms/uploads/php/files/50vr6v7705juuq524grl8cvhu6/bigujuzefozinen.pdfIn PDF document text
    • https://www.sahabatkeluargahomecare.com/wp-content/plugins/formcraft/file-upload/server/content/files/16103eb7f37505---21933658871.pdfIn PDF document text
    • http://slsnn.ru/content/file/nisowalafesuxojawi.pdfIn PDF document text
    • https://laps.pl/userfiles/file/tagelozadizakafufidufipel.pdfIn PDF document text
    • http://www.radioemka.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b82b338924a---seposa.pdfIn PDF document text
    • https://onhimalayas.com/ckfinder/userfiles/files/10353571488.pdfIn PDF document text
    • https://buka.ru/sadm_files/37971183440.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_off0000dbdc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDBDC 18984 bytes
SHA-256: a59f3d7c8053fac073ca16f9851bd0a00750d33aa030e7cce3d78edce5864c23
font_01_sfnt_off00010b5c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10B5C 10880 bytes
SHA-256: c7f05d987e5c4aa97e739bfe9193e96581d28cc0eb5f4f32e89f993d6aceb25d
font_02_sfnt_off0001245c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1245C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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