Malicious PDF — malware analysis report

Static analysis result for SHA-256 88f8d695434db049…

MALICIOUS

PDF

71.3 KB Created: 2021-06-24 19:59:37 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-29
MD5: ff4dd24eb929dcdd9b8e4f57e0936d55 SHA-1: 59910a8c5935142e68d871706cb98b1c9a2f5197 SHA-256: 88f8d695434db0493c82dd48680f09280baf88d973f226c065a98ecfbd632392
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

This PDF file is identified as malicious by ML classifiers and ClamAV, indicating a phishing or trojan threat. It functions as a link farm, hosting numerous links to other PDF files on compromised WordPress sites, likely to distribute further malware or phishing content. The document body, though heavily obfuscated, contains a lure related to 'acid base titration lab questions and answers' to entice users to click the embedded malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 7

  • 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.
  • Urgency / deadline lure low SE_URGENCY_LURE
    Document contains urgency or deadline language ('account will be terminated', 'action required within 24 hours', etc.) — useful context, but low-signal without other findings
  • 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://smidgel.ru/uplcv?utm_term=acid+base+titration+lab+questions+and+answers PDF link annotation
    • http://prodesign31.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1607bd7bb6ec8f---vebozapiputoxedut.pdfIn PDF document text
    • http://hongshengfish.com/uploadfiles/20210516/210516105640325236r7btop22kglg.pdfIn PDF document text
    • http://alpha-cp.com/userfiles/file/79724758529.pdfIn PDF document text
    • https://www.sgestrecho.es/wp-content/plugins/formcraft/file-upload/server/content/files/160a96970aae98---53649152783.pdfIn PDF document text
    • https://rts-wm.com/ckfinder/userfiles/files/kipuzadujesuwubemewi.pdfIn PDF document text
    • https://autoroman-service.ro/imagini_ws/pezoxiwulovopikaw.pdfIn PDF document text
    • http://aryajob.com/user_upload/file/30467579852.pdfIn PDF document text
    • http://dataction.org/demo/dataction/media/nimijorixoxotude.pdfIn PDF document text
    • https://pankalconstructora.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608ee7ab49a23---14058256507.pdfIn PDF document text
    • https://biothiennam.com/media/ftp/file/rozokovigotofixitazarun.pdfIn PDF document text
    • https://fruzsiflame.hu/userfiles/file/59165187453.pdfIn PDF document text
    • https://anpheatingandac.com/nbloom/fckuploads/file/53919744792.pdfIn PDF document text
    • https://pt2-turbo-j3t.com/contents//files/64486389998.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn 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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d81d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD81D 5280 bytes
SHA-256: b3afe3faad19695b8c937aeb10d70e1216f6f4fb46391728d7b1d9e139f34102
font_01_sfnt_off0000ea2c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEA2C 11236 bytes
SHA-256: e5c57e19f788be743a8ef0a086eedd7b376a90e6637268e84d82c76a8a25b3a2

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