Malicious PDF — malware analysis report

Static analysis result for SHA-256 4a16eb0e5db5b6fb…

MALICIOUS

PDF

79.4 KB Created: 2021-06-05 05:26:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-16
MD5: 67f6e3bd639337830029b7d2b7b8a0a0 SHA-1: ef6194d3d50b7e7c16596e00bc5c47fec4729774 SHA-256: 4a16eb0e5db5b6fb00d70e9a1e763dbb28693716d43a3e84b3a758bde7458594
156 Risk Score

Malware Insights

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

This PDF file was flagged by ClamAV as Pdf.Phishing.Trojan and a machine learning classifier indicated a high probability of maliciousness. It contains numerous links, many pointing to compromised WordPress sites, suggesting it functions as a link farm to distribute phishing or malware. The document body is heavily obfuscated and contains metadata indicating it was generated by wkhtmltopdf, a tool often used to create PDF versions of web pages.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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://krisoc.ru/uplcv?utm_term=cons+of+norm+referenced+test PDF link annotation
    • http://admio.ru/wp-content/plugins/formcraft/file-upload/server/content/files/16079e61769841---guzesupilijanemi.pdfIn PDF document text
    • https://gearforfree.com/wp-content/plugins/super-forms/uploads/php/files/1mpki4bov0208duofr144qod1o/90617283274.pdfIn PDF document text
    • https://mindweave.co.uk/wp-content/plugins/super-forms/uploads/php/files/gpmj4tvskg9aen8n85iuq9h6pf/dewojasaror.pdfIn PDF document text
    • http://au-zlato.sk/upload/files/6963680343.pdfIn PDF document text
    • http://www.zulfugar.nl/wp-content/plugins/formcraft/file-upload/server/content/files/16095a0884c009---galimubusaxizusejikoda.pdfIn PDF document text
    • https://prairieroseclothiers.com/FCKeditor/file/88013386017.pdfIn PDF document text
    • https://monacollection.ua/wp-content/plugins/super-forms/uploads/php/files/a99e58b5143fa36dcb54e21a4a4c7f90/28867769277.pdfIn PDF document text
    • https://www.penyembuhanholistikreiki.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a11622048ab---51892496225.pdfIn PDF document text
    • http://okmarin.ru/userfiles/file/povuzoripejij.pdfIn PDF document text
    • https://akapacha.com/userfiles/file/79495752507.pdfIn PDF document text
    • http://logo4you.dk/userfiles/file/21348902247.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608b03679b239---vumapax.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://www.daltonmaag.com/In 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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ef23.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEF23 4688 bytes
SHA-256: 307ac35e8b8073cbfb848956e99ea4dbd72f1536b2945f081d59923c66ff39e3
font_01_sfnt_off0000feec.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFEEC 10500 bytes
SHA-256: b4cd6b31b766248d2834af3c2943b7a37328292e26950084beca122fb2779a70
font_02_sfnt_off0001227b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1227B 4324 bytes
SHA-256: ce7e2e230a41ba6fc2d7d2240890c8289d67876d84a3d076d67c0b48111c8230

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