Malicious PDF — malware analysis report

Static analysis result for SHA-256 3bd61f8d99a3638a…

MALICIOUS

PDF

73.2 KB Created: 2021-06-11 23:54:00 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-11
MD5: 7e9aaf86e740cafb403c4722039578bf SHA-1: c711ffc1fcfb5ca60e7158934271b5b231f3ce0d SHA-256: 3bd61f8d99a3638a6446def37b65ef68aef2d2fe34bb6da5f764b5d0b2613147
172 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript T1203 Exploitation for Client Execution

The PDF contains embedded JavaScript and multiple URLs pointing to compromised websites, suggesting it's designed to deliver a malicious payload. The heuristic firings indicate a link farm strategy and ClamAV detection confirms its malicious nature, likely as a phishing or trojan delivery mechanism. The document body, though heavily obfuscated, contains text related to 'teacher's book pdf' and 'wkhtmltopdf', likely a lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 8

  • 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.
  • 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.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://pistant.ru/uplcv?utm_term=upstream+proficiency+teacher%2527s+book+pdf PDF link annotation
    • http://asiadomainstore.com/userfiles/file/21100069580.pdfIn PDF document text
    • https://www.glasswindowequipment.com/wp-content/plugins/super-forms/uploads/php/files/6e44137591a91da3e955da5af08cccf0/40134842707.pdfIn PDF document text
    • http://www.argentum.com/wp-content/plugins/super-forms/uploads/php/files/61n1nj5uakkvt399594r332svq/fewurodunonebimelumeva.pdfIn PDF document text
    • https://www.bouwenaaneensterkwerkgeversmerk.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160ab14d61174f---kanobisesi.pdfIn PDF document text
    • https://aspirans.com/files/file/35451225615.pdfIn PDF document text
    • https://www.hagensmarketing.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bca1083242a---1928492363.pdfIn PDF document text
    • http://aihyang.com/userfiles/file/zejikora.pdfIn PDF document text
    • https://mercedesmazo.es/wp-content/plugins/formcraft/file-upload/server/content/files/1607ebaf28af68---9330397488.pdfIn PDF document text
    • http://xn--2vxr09c6mc.tw/CKEdit/upload/files/78315983994.pdfIn PDF document text
    • http://aldara-latinoamerica.com/userfiles/file/bijinugomizavupeb.pdfIn PDF document text
    • https://choiceenergynetwork.com/wp-content/plugins/super-forms/uploads/php/files/a7c00a5a4d9a22df617060686c4847f7/diloxegitakisodip.pdfIn PDF document text
    • https://markzone.az/wp-content/plugins/super-forms/uploads/php/files/rtc5vijat3tu0dnh8hvtkn20t2/44608141376.pdfIn PDF document text
    • https://goldenparadisestsimons.com/wp-content/plugins/super-forms/uploads/php/files/e65cce0a6d30d14788129d805339f0e0/76905805438.pdfIn PDF document text
    • http://epoch-making.jp/js/upload/files/goxewo.pdfIn PDF document text
    • http://asja-doll.ru/userfiles/file/96744050359.pdfIn PDF document text
    • http://charugarware.com/DEVELOPMENT/charu_garware/uploaded/userfiles/file/desebuzonakefe.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_off0000c8fa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC8FA 5480 bytes
SHA-256: 01928040884ca1b951ad5b4cf2f210189ef603099e6fe6b0d5906bc85dc66fac
font_01_sfnt_off0000db72.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDB72 14904 bytes
SHA-256: 6d5612677609520fe2b4c5ea912d84229be6e594f0261fc9a962c43d41deaed8
font_02_sfnt_off0001098d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1098D 4324 bytes
SHA-256: 9f355172d696dda274cac500966718f112ce76951f19577ac4888987ea6471b2

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