Malicious PDF — malware analysis report

Static analysis result for SHA-256 4a3db640ff41c131…

MALICIOUS

PDF

85.2 KB Created: 2021-09-06 12:43:45 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: b43b76eeeb9d38110e100f32957bc84c SHA-1: 76f031f03651161f7826980df42302ec8eb94282 SHA-256: 4a3db640ff41c131b32adc6a930f2bc11d21c284690157f1ccd8ea507d39255f
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains a large number of external URIs, many of which point to compromised WordPress sites or disposable hosting, indicating a link farm designed for malicious redirection. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware distribution. Although no scripts were explicitly extracted, the nature of the link farm and the detection results point towards an attempt to lure users to malicious sites, aligning with T1566.001 (Spearphishing Attachment) as a likely initial access vector.

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://krisoc.ru/uplcv?utm_term=comma+usage+quiz+pdf PDF link annotation
    • https://habibitours.com/ckfinder/userfiles/files/63817137263.pdfIn PDF document text
    • https://humantouchtranslations.com/wp-content/plugins/formcraft/file-upload/server/content/files/1/1608738be1de7a---28805896658.pdfIn PDF document text
    • https://mwasafat.com/uploads/files/18364071254.pdfIn PDF document text
    • https://xn--78-6kce7dfhb9dwb.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/1ac3522c37ac9591f3daedc94a7c6dcc/91070382748.pdfIn PDF document text
    • https://www.marthatrotts.ca/wp-content/plugins/formcraft/file-upload/server/content/files/16070c245055e1---64860377956.pdfIn PDF document text
    • https://theurbanthinktank.com/files/15548873439.pdfIn PDF document text
    • http://manufim.co.il/wp-content/plugins/formcraft/file-upload/server/content/files/1609612aa29a1e---joxerajugotudive.pdfIn PDF document text
    • http://gospel-pour-100-voix.com/fichiers/newsletter/file/kebugerima.pdfIn PDF document text
    • http://caycanhtuyhien.com/uploads/image/files/73198020468.pdfIn PDF document text
    • http://occahomesearch.com/userfiles/files/277661276.pdfIn PDF document text
    • http://dastone.ru/userfiles/file/lowomebaxot.pdfIn PDF document text
    • http://htygroup.com/upload/files/38102273944.pdfIn PDF document text
    • https://christianboudreau.com/wp-content/plugins/formcraft/file-upload/server/content/files/16103bd61ed4ec---78102840572.pdfIn PDF document text
    • http://phuocthuan.vn/images/pic/file/18553324799.pdfIn PDF document text
    • https://www.ideaklinikbakirkoy.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ae2f690a162---84993256344.pdfIn PDF document text
    • http://maynenkhiinverter.com/media/ftp/file/valodipopokogotopimori.pdfIn PDF document text
    • https://www.advids.io/wp-content/plugins/formcraft/file-upload/server/content/files/16071b2f6de0b3---bafin.pdfIn PDF document text
    • http://womenshealthcarenp.com/clients/2/29/29a32d4da59f0b4eaa4573e1354aeabc/File/55138127560.pdfIn PDF document text
    • http://abpaluso.com/upload/file/kavibugabavar.pdfIn PDF document text
    • https://psychotherapie-dr-albrecht.de/wp-content/plugins/formcraft/file-upload/server/content/files/160c8e6e31e500---3849809329.pdfIn PDF document text
    • https://amezdigital.com/wp-content/plugins/super-forms/uploads/php/files/ad279576eb01fa1199abd0a621fac4aa/jademumuxed.pdfIn PDF document text
    • https://alrukn.co/userfiles/files/70353111708.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_off0000e77b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE77B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000ff8d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFF8D 18300 bytes
SHA-256: 74172a6af08570faddd7759b5599ace6938d7df2c6ded08523e7c8dac46b0be2
font_02_sfnt_off00012ee9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12EE9 10832 bytes
SHA-256: 5eccb0272a7a0e42aa1c63b5d6249b7b6be3e11ffe49769c295b18d0ba4f52a8

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