Malicious PDF — malware analysis report

Static analysis result for SHA-256 b5cfe3cb382fbba6…

MALICIOUS

PDF

81.0 KB Created: 2021-09-08 16:10:37 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 4666015700ba5172bf42b6b69f9654e3 SHA-1: d1a73a8eeea87bcba3585a5761a5000803fbf4c3 SHA-256: b5cfe3cb382fbba68d2954d2edb2dd414b955f4101829ac8e45e05b2884fe8ea
184 Risk Score

Malware Insights

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

The sample is a PDF containing embedded JavaScript and multiple external URIs, many of which point to compromised WordPress sites acting as link farms. The ML classifier and ClamAV detection strongly indicate maliciousness. The presence of embedded JavaScript suggests an attempt to execute code, likely to redirect the user to a malicious site or download a secondary payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

Heuristics 8

  • 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.
  • Callback phishing phone lure medium SE_CALLBACK_LURE
    Document asks the user to call a phone number in billing, refund, subscription, fraud, or security context — consistent with callback phishing or tech-support scam patterns. Suppressed for legitimate-issuer (IRS/gov/official-form) documents that carry no urgency or charge/dispute escalation.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://www.heainc.com/wp-content/plugins/formcraft/file-upload/server/content/files/16137e81ff3a4a---27962833367.pdf In PDF document text
    • http://klhl.com/userfiles/file/bisokuxasonatedore.pdfIn PDF document text
    • http://prtourusa.com/FileData/ckfinder/files/20210902_86BC90267FE0FF40.pdfIn PDF document text
    • https://www.cylinder96.ru/admin/ckfinder/userfiles/files/ronoliduxedefepig.pdfIn PDF document text
    • http://es-umzuege-transporte.de/wp-content/plugins/super-forms/uploads/php/files/7f5af7409aeaea76c564f82cf7527265/lufotemapi.pdfIn PDF document text
    • https://ietc-oman.saktoon.com/userfiles/files/litajuvap.pdfIn PDF document text
    • https://norservis.info/files/files/jobezafixogow.pdfIn PDF document text
    • http://liceoadultos.juniorcollege.cl/userfiles/files/1287906332.pdfIn PDF document text
    • https://glaze-metalart.com/upload/files/38373310452.pdfIn PDF document text
    • http://ketphatthinh.vn/upload/files/babiguvagiz.pdfIn PDF document text
    • http://asu.com.vn/wp-content/plugins/super-forms/uploads/php/files/e4foiu558sh3g65kc656uv4l57/jaxuko.pdfIn PDF document text
    • http://songhakbbq.com/uploads/files/23735973168.pdfIn PDF document text
    • https://hoanghaie.com/Images_upload/files/kujebi.pdfIn PDF document text
    • https://alfa-clining.ru/wp-content/plugins/super-forms/uploads/php/files/baf2eee1e092b779443ba918625e06f4/95095066200.pdfIn PDF document text
    • http://teresachild.com/upload/files/93548946937.pdfIn PDF document text
    • https://infravoip.com/wp-content/plugins/super-forms/uploads/php/files/6a76d6abe8918fcea656bb3304f8cf60/dovizokifimofekibi.pdfIn PDF document text
    • https://officialbacknumber.org/editor_up/lozukibijenorimobazuma.pdfIn PDF document text
    • http://nhuaduongnhapkhauaz.info/upload/files/lukisabafabusep.pdfIn PDF document text
    • http://marketingnews.fr/images/file/78493347800.pdfIn PDF document text
    • http://etrustmi.com/ckfinder/userfiles/files/xipetorafozok.pdfIn PDF document text
    • http://fabriquetextil.com/js/new/fckeditor/userfiles/file/10887190984.pdfIn PDF document text
    • http://quinta.cl/upload/files/tanerujasetewol.pdfIn PDF document text
    • https://gppacdatabase.net/userfiles/file/68246251841.pdfIn PDF document text
    • http://ducthoaudio.com/upload/files/48901791000.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/Om9ozkHLxGw/uplcv?utm_term=workstation+hp+z240+pdfPDF 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_off0000d4ab.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD4AB 10880 bytes
SHA-256: 2537ba3f3dfbab9b45078c6a64d82b73fae8a4c8a72b6df49830642d62128162
font_01_sfnt_off0000eddd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEDDD 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000105ef.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x105EF 18628 bytes
SHA-256: 906affe20cc735893308f678b43ed7c630b6fc4705b5c2b93ff66011e2f1c523

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