Malicious PDF — malware analysis report

Static analysis result for SHA-256 9cf8c86f95023bfa…

MALICIOUS

PDF

81.1 KB Created: 2021-05-07 07:48:20 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-27
MD5: 6c54e422a23a245b612b91e359faa5d8 SHA-1: 53c258272f7649731410e072c4bc18a0ede2d5e2 SHA-256: 9cf8c86f95023bfa8760d46bd0fcd6ede7b2eb42e1a37ed2227787edf606ac59
244 Risk Score
Tags
free-cdn-ebook-manual-lure

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The sample is a PDF file identified as malicious by ClamAV and an ML classifier. It contains numerous embedded links, with one critical heuristic indicating a link to known malicious redirector infrastructure. The document body, though heavily obfuscated, suggests a lure related to an 'introduction to embedded systems' solution manual, which is likely a pretext for directing users to malicious sites. No scripts were extracted, but the presence of malicious links and the overall structure strongly suggest a phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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 links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK
    PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • 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.
  • 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://yafferge.ru/strik?utm_term=introduction+to+embedded+systems+a+cyber-physical+systems+approach+solution+manual In PDF document text
    • https://cdn-cms.f-static.net/uploads/4369936/normal_601ca5bd26d0a.pdfIn PDF document text
    • https://fuvuliles.weebly.com/uploads/1/3/4/9/134904701/80e3663371.pdfIn PDF document text
    • https://lomewulepizava.weebly.com/uploads/1/3/3/9/133999744/nokuxu-kidowi-pupivisari-zupexu.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4369161/normal_60036c8bc56a2.pdfIn PDF document text
    • https://xokekomoto.weebly.com/uploads/1/3/4/5/134598663/tuxebafubifad.pdfIn PDF document text
    • https://bikirufiw.weebly.com/uploads/1/3/1/4/131452989/xelezojofon.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://s3.amazonaws.com/latufenaw/guwevajudujalutobabesivez.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/f24ede43-4276-48a4-a311-15d92b16809a/are_forklift_certification_cards_required_by_osha.pdfIn PDF document text
    • https://9907981b-0bc7-4fd3-a434-169f7cdadf42.filesusr.com/ugd/575363_752b23d3a0c44318b3357041b27277bf.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/varolexexus/bevidenajorevanafujoma.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/f105aebd-5199-4850-b66b-5e341bb41aba/what_to_write_my_college_essay_on_quiz.pdfIn PDF document text
    • https://0fecb50d-c8db-4b5c-a67e-01a13b1c0e9a.filesusr.com/ugd/da7c2d_874953d112b5440e83efc54d77443f50.pdf?index=trueIn PDF document text
    • https://973697ad-ffa4-4f9d-85cd-0c9d1ea039ee.filesusr.com/ugd/5f5755_ade98f28134f403abcd6f25ddae95127.pdf?index=trueIn PDF document text
    • https://efa91360-7c21-416c-9d60-3189e0beb381.filesusr.com/ugd/42ffc7_f0f525e586e041848f41b55382013d7f.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/ab301179-2989-4809-96cd-33bd42772680/dirisoxusopek.pdfIn PDF document text
    • https://332892e0-6a2b-40ad-946e-e7c92c61c867.filesusr.com/ugd/3e5d97_8616f5ca6bc24b08a20e260c9a5f72a1.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/sabegokek/romantic_good_night_image_hd.pdfIn PDF document text
    • https://493f174a-a540-412c-bacb-e5b7b26cbfcf.filesusr.com/ugd/95bb70_9a58746607e94a5b99b4354df299c85c.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/bokelur/benzhou_yy50qt-6_l.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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000fc1d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFC1D 5524 bytes
SHA-256: bd50b6107a0de19b272ba6e3443eab1d38b24e5dc1b192bb6803a24df7d963b5
font_01_sfnt_off00010eb8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10EB8 11564 bytes
SHA-256: 23c02851e1b91b7b00c6d51b12d148f3d68ffc40de60a84694381f23b073b43e

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