Malicious PDF — malware analysis report

Static analysis result for SHA-256 836873caa3a5209e…

MALICIOUS

PDF

71.8 KB Created: 2021-10-04 00:10:53 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-02
MD5: e16cd320ad4d0c91244e647555c2bc95 SHA-1: 77ec817ef4686898ad74b22c0ef656d652bf6b2b SHA-256: 836873caa3a5209ef8682921e35d3fa1c2f0860bdcc0f2e1da4eed4875547ef5
156 Risk Score

Malware Insights

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

The PDF file was flagged by multiple heuristics and a machine learning classifier as malicious, with ClamAV identifying it as a phishing trojan. It contains numerous links to external websites, many of which appear to be hosted on compromised or disposable domains, suggesting a link farm designed to redirect users to malicious content. The presence of 'utm_term' parameters in some URLs indicates a potential phishing or SEO manipulation tactic.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9947

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://archism.ru/uplcv?utm_term=this+the+sound+of+the+police PDF link annotation
    • http://energosol.pl/images_cms/file/42689001264.pdfIn PDF document text
    • http://gibisch.org/files/files/73520839329.pdfIn PDF document text
    • http://deborahkay.com/ckfinder/userfiles/files/wukezojabirijekodaza.pdfIn PDF document text
    • https://komunalno-vrgorac.hr/files/kixitaru.pdfIn PDF document text
    • http://aalzkj.love-mrt.com/upload/files/noruja.pdfIn PDF document text
    • https://gamletaarnhuset.no/wp-content/plugins/formcraft/file-upload/server/content/files/16156ffc7744ad---veziruroforav.pdfIn PDF document text
    • http://wwsm-hk.com/files/file/90366237197.pdfIn PDF document text
    • http://kemnhapkhau.com/upload/files/nivivoresogijes.pdfIn PDF document text
    • https://chingchia.com/uploads/files/202109220900244534.pdfIn PDF document text
    • http://grandioso.asia/editor_upload_image/file/15207673066.pdfIn PDF document text
    • https://almuhja.net/ckfinder/userfiles/files/mesibupekazetediripeboke.pdfIn PDF document text
    • http://24x7taazasamachar.com/assets/ckfinder/core/connector/php/uploads/files/87526425479.pdfIn PDF document text
    • http://carrasvilla.es/uploads/files/raduterivudunuvorufatu.pdfIn PDF document text
    • http://www.telsercom.com/wp-content/plugins/formcraft/file-upload/server/content/files/16134ccd471fd4---96160297032.pdfIn PDF document text
    • http://emirates-offshore.com/uploads/image/file/xevuwegevapa.pdfIn PDF document text
    • http://carszana.com/image/upload/File/girebaxo.pdfIn PDF document text
    • https://luathoanghuy.com/uploads/files/larazabodeg.pdfIn PDF document text
    • https://felixtrail.com/imagini_ws/87298920250.pdfIn PDF document text
    • http://www.qookspot.kitchen/wp-content/plugins/formcraft/file-upload/server/content/files/161536e9a2f506---xenopenokinijo.pdfIn PDF document text
    • http://somkuthyoptika.hu/editor_up/35440101906.pdfIn PDF document text
    • https://emartdeko.pl/galeria/file/jogagewosox.pdfIn PDF document text
    • http://dui-antidote.net/images/userfiles/file/xigixa.pdfIn PDF document text
    • http://apartamentykunickiego.pl/architekci/public/upload/ckfinder/userfiles/files/97631977089.pdfIn PDF document text
    • http://elliptical-trainers.ru/ckfinder/userfiles/files/60896179494.pdfIn PDF document text
    • http://rootbeadmill.com/upload_fck/file/2021-9-16/20210916105102221908.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_off0000b50f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB50F 17648 bytes
SHA-256: 22ee242cc34864d5cc006d776518075424e12b2e994826cd0ba37d8090f55167
font_01_sfnt_off0000e1dc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE1DC 10520 bytes
SHA-256: 154e8f7564ae21cf254f76e2a04fa6c9c2a918d297d49830500aa84fd774f879
font_02_sfnt_off0000f9bf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF9BF 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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