Malicious PDF — malware analysis report

Static analysis result for SHA-256 bc40139cd625d9bd…

MALICIOUS

PDF

121.3 KB Created: 2021-10-23 03:58:05 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-07
MD5: 9eac0434a130d64fe6b698234dc7997b SHA-1: a6367f55cea9208a42287c22ee4ca3d69545cff8 SHA-256: bc40139cd625d9bd4e3de6b642221a18413950264c03b1c476d4c28d7ba0a2cc
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF file contains numerous embedded URLs that point to other PDF documents hosted on various domains. Several heuristics indicate this is a link farm, with some links pointing to compromised WordPress upload storage. The ClamAV detection and ML classifier strongly suggest malicious intent, likely phishing or malware distribution through these linked documents.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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=politeness+brown+and+levinson PDF link annotation
    • http://phukhoabacninh.com/images/files/mizikakuragok.pdfIn PDF document text
    • http://curry-box-deluxe.de/userfiles/file/61041951732.pdfIn PDF document text
    • https://aspirecambodia-edu.org/userfiles/file/15330387864.pdfIn PDF document text
    • https://sy-chemical.com/UserFiles/file/72676344059.pdfIn PDF document text
    • http://xn--9w3b270a7kf.kr/data/editor/file/17522274540.pdfIn PDF document text
    • http://studioego.cz/userfiles/file/95160369748.pdfIn PDF document text
    • https://drmiamiconnect.com/wp-content/plugins/super-forms/uploads/php/files/4a0b65c34194287f2c5076b10c857941/wuloxaziraf.pdfIn PDF document text
    • http://maility.pl/_ADRESuserfiles/file/vexepagivaxuk.pdfIn PDF document text
    • https://szallas-karpatalja.hu/upload/sijasexeperirarid.pdfIn PDF document text
    • http://waetsukai.jp/system/ckfinder/userfiles/files/73113057543.pdfIn PDF document text
    • https://oneremote.ru/wp-content/plugins/super-forms/uploads/php/files/c430d002bed126087adfe235c3d042f0/dowavebokugepe.pdfIn PDF document text
    • https://rmdschoolandcollege.com/wp-content/plugins/super-forms/uploads/php/files/4990bee70edcc12ea161c97ec6f14d49/mujago.pdfIn PDF document text
    • http://erodiertechnik-wenzel.de/userfiles/file/tigizurafowivu.pdfIn PDF document text
    • https://bentzendesign.se/wp-content/plugins/formcraft/file-upload/server/content/files/16167dd79b49f0---kerodi.pdfIn PDF document text
    • https://poojaindiangrill.com/nbloom/fckuploads/file/xigoximomusokudak.pdfIn PDF document text
    • http://thebeautyofdesign.nl/ckfinder/userfiles/files/74891100871.pdfIn PDF document text
    • http://famcareconnect.org/wp-content/plugins/formcraft/file-upload/server/content/files/1616169219ca98---jabapavakunez.pdfIn PDF document text
    • http://cofetariafraguta.ro/UserFiles/file/faxirimulis.pdfIn PDF document text
    • http://dxqzx.com/ckfinder/userfiles/files/20210904_055936.pdfIn PDF document text
    • http://ch-bovi.com/upload/files/mirebi.pdfIn PDF document text
    • http://skncn.com/u/files/zumavipikoxuzozeromu.pdfIn PDF document text
    • https://vwb.mrv-educationservices.com/content_file/files/tubavixufisida.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_off00016bac.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x16BAC 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off000183be.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x183BE 22688 bytes
SHA-256: 85c6cad40d6eb1ba73292ae68d2b2ff4937f5d93080c2c12f05b3e7348100fc2
font_02_sfnt_off0001bf78.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1BF78 10536 bytes
SHA-256: 42e21faa5071028b6aa15082d25941f4b224895d6d7ed2b2dfebdfda1fe5264e