Malicious PDF — malware analysis report

Static analysis result for SHA-256 81633cd4078b9b74…

MALICIOUS

PDF

86.1 KB Created: 2021-07-14 07:29:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: bbb45f5486e0d711c0ab3715df6cb510 SHA-1: 93b424a114a8310ac53de78f5643962eca73a8eb SHA-256: 81633cd4078b9b74c71ffdd774da1749aa92a52eadde14f2cbd8244584f72f0b
156 Risk Score

Malware Insights

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

The PDF contains numerous links pointing to compromised WordPress sites, suggesting a link farm designed to obscure the ultimate destination. The ClamAV detection and ML classifier strongly indicate malicious intent, likely phishing or malware distribution. While no scripts were extracted, the structure and URL patterns are consistent with a phishing lure or a downloader for a second-stage payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9942

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://ne-moloko.ee/wp-content/plugins/super-forms/uploads/php/files/a18f4a77220d761d444270425c1ea83c/6856985515.pdf In PDF document text
    • http://argyler.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607a826d3cc95---10909638216.pdfIn PDF document text
    • https://alkhairi.co.uk/wp-content/plugins/super-forms/uploads/php/files/ab3de5fb88cbb3e236afbcfdc9eebf78/7390758759.pdfIn PDF document text
    • https://greenturtleproductions.com.au/wp-content/plugins/super-forms/uploads/php/files/41208d4b814ae795f32164da2b294e58/xovibaxefapevuvox.pdfIn PDF document text
    • http://w-f-l.de/user_img/file/jaketutanatezijagukun.pdfIn PDF document text
    • http://www.carolglassman.com/wp-content/plugins/formcraft/file-upload/server/content/files/16072fd795169c---tewimawadiwit.pdfIn PDF document text
    • https://autosaloncenter.com/uploads/file/76940115094.pdfIn PDF document text
    • https://trsbarriersdirect.com/wp-content/plugins/super-forms/uploads/php/files/obf7lk6e5jg15l4slb6a05o4os/lirijifugatuwakux.pdfIn PDF document text
    • https://acethamessecurity.co.uk/wp-content/plugins/super-forms/uploads/php/files/e90d740d415924677086f2316fac3827/42291121274.pdfIn PDF document text
    • https://masini-de-ambalat.ro/images/userfiles/muforovibifetovebisexezu.pdfIn PDF document text
    • http://historia-bfured.hu/userfiles/file/59042873212.pdfIn PDF document text
    • http://loveperfectionschool.com/upload/file/60655841773.pdfIn PDF document text
    • https://kamber.dk/wp-content/plugins/super-forms/uploads/php/files/cf28731fc4f3eb7bc0cc8cef12e9e877/fowunukegevobupajonuzoram.pdfIn PDF document text
    • https://islandsvefir.is/wp-content/plugins/super-forms/uploads/php/files/69cpcuvhqvgdckj67v78ra2nsg/93174137559.pdfIn PDF document text
    • https://www.digitalsofts.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c301a26444b---71427455520.pdfIn PDF document text
    • https://impariant-club.ru/wp-content/plugins/super-forms/uploads/php/files/dd9f87a4afe5cc1b42853b61639c9edb/31341643783.pdfIn PDF document text
    • https://a1-recruitment.fr/v2011/Files/fck_upload/file/wezunovufawegijibud.pdfIn PDF document text
    • http://banlinhkienlaptop.com/userfiles/file/bewuzetowet.pdfIn PDF document text
    • https://espaciocultivarte.com/ckfinder/userfiles/files/wifatemuvalesevupuwinuru.pdfIn PDF document text
    • http://www.aluvascientific.com/UserFiles/file/dijaritapuxuximavasijopuk.pdfIn PDF document text
    • https://tfnd.org/wp-content/plugins/super-forms/uploads/php/files/022ee58d2a35659f27a0d796c694069d/66455538440.pdfIn PDF document text
    • https://www.fecomerciomg.org.br/wp-content/plugins/formcraft/file-upload/server/content/files/1607c4b7c57909---80778754462.pdfIn PDF document text
    • http://www.cuerpomenteyespiritu.es/wp-content/plugins/formcraft/file-upload/server/content/files/16092505af08ab---favoridixagatizanudibi.pdfIn PDF document text
    • http://piecco.eu/upload/files/52614132340.pdfIn PDF document text
    • http://sanitaerprofi.ch/fckeditor/editor/images/file/98459410474.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/fzgW7-mxBc0/uplcv?utm_term=ancient+greece+answer+keyPDF 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_off0000f0cb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF0CB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off000108e2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x108E2 10512 bytes
SHA-256: 91897793ba0d143473f12300f272ff88001e01a1d1f33f381c34061bd6da8b9d
font_02_sfnt_off0001210a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1210A 16296 bytes
SHA-256: 6ac35aacef1d3b00e56f48f9a1dfd30386eefd1ca541e52b2487d7bcb87393d3