Malicious PDF — malware analysis report

Static analysis result for SHA-256 5d81815f8b5845d3…

MALICIOUS

PDF

88.7 KB Created: 2021-09-20 05:18:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-31
MD5: c0b81378944f0a88f2be7411614c81fd SHA-1: 166d7fc794a81516fe5e59309547d753555c6b54 SHA-256: 5d81815f8b5845d3e2c7347e9ed1114f36ed3299c8a637f41a256eea98864a32
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The ML classifier and ClamAV detection strongly indicate malicious intent. The PDF contains numerous external links, many pointing to compromised WordPress uploads or disposable hosting, suggesting a link farm or phishing lure. The presence of embedded URLs and the PDF_SEO_DISPOSABLE_LINK_FARM heuristic further support this, indicating the document's primary purpose is to redirect users to potentially harmful external sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9942

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://synerhu.ru/uplcv?utm_term=geetha+govindam+telugu+movie+full+movie PDF link annotation
    • http://manegedebuitenwijck.nl/uploads/file/netadituxagexores.pdfIn PDF document text
    • https://manuscripthandler.com/userfiles/file/27892614755.pdfIn PDF document text
    • https://galerie-louise.be/userfiles/files/xekono.pdfIn PDF document text
    • http://happyhanool.com/ckupload/files/40002761255.pdfIn PDF document text
    • http://hlqh.net/userfiles/file/20210916024909_1920521104.pdfIn PDF document text
    • https://harley.dataroom.tw/upload/files/tumuwanonepuririf.pdfIn PDF document text
    • http://birkhoffhi.com/userfiles/files/vipawu.pdfIn PDF document text
    • http://namlinhchisapa.com/userfiles/image/file/70980806668.pdfIn PDF document text
    • https://guanlai.tw/uploads/files/202109121910353449.pdfIn PDF document text
    • http://chocoenglish.com/_UploadFile/Images/file/61689774568.pdfIn PDF document text
    • http://dpholding.ru/uploads/files/jusenuzodod.pdfIn PDF document text
    • http://xn----7sbab1bcaqplb0ccyi9d.xn--p1ai/files/file/48477751433.pdfIn PDF document text
    • https://kayakbranson.com/wp-content/plugins/formcraft/file-upload/server/content/files/16144fb8538f15---72017773304.pdfIn PDF document text
    • http://pmrs.ps/userfiles/file/91393901799.pdfIn PDF document text
    • http://eugensa.lt/app/webroot/uploads/userfiles/files/68854663317.pdfIn PDF document text
    • http://jiachuankeji.com/upload_fck/file/2021-9-20/20210920062341939786.pdfIn PDF document text
    • http://eduomania.com/wp-content/plugins/formcraft/file-upload/server/content/files/16134ef2a47f69---19321596341.pdfIn PDF document text
    • https://htfcompact.com/wp-content/plugins/super-forms/uploads/php/files/09dab60fe3e3d2dda8d405fb684dc4e1/zaborevegibewogonofexu.pdfIn PDF document text
    • http://sztarmedia.hu/_user/file/nirebafizifenavesegadek.pdfIn PDF document text
    • https://sabresources.com/FCKuploads/file/51449418527.pdfIn PDF document text
    • http://www.azurwelcomeservices.com/userfiles/file/28776517250.pdfIn PDF document text
    • http://associatedreclaimed.com/userfiles/files/69701975365.pdfIn PDF document text
    • http://timatey.kz/wp-content/plugins/super-forms/uploads/php/files/s12epnbppcb1d2432eut23u402/sunelajunixaraputojevova.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_off0000f555.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF555 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00010d6c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10D6C 10736 bytes
SHA-256: e9ecb282eaf470783653eb52e434eceb8ddf44eaf095ebca79f4d849b950cbfb
font_02_sfnt_off000125bd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x125BD 18368 bytes
SHA-256: c67b49fdeffbf70ae5c172ae376700852e9bc7fc362f8b3fd2eb3c831bba1754