Malicious PDF — malware analysis report

Static analysis result for SHA-256 b109b91f39c9b94f…

MALICIOUS

PDF

83.1 KB Created: 2021-04-08 01:13:16 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-08-25
MD5: 659fff20dafdc549431eaf87e702fe2c SHA-1: db2ce8411220275b70788811816911118a2dbade SHA-256: b109b91f39c9b94fbf2e4369daee84653e0f0c0ec0570d2c3c19c9e74d2cd312
186 Risk Score
Tags
free-cdn-ebook-manual-lure

Malware Insights

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

This PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. The PDF contains a large number of external links, many pointing to disposable hosting, suggesting it functions as a link farm. One of the primary URLs extracted is https://jacksth.ru/wix?keyword=blown+to+bits+chapter+3+reflection+questions, which appears to be a lure for SEO manipulation or potentially phishing. No scripts were extracted, but the PDF structure itself facilitates the redirection to these external sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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.
  • 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://jacksth.ru/wix?keyword=blown+to+bits+chapter+3+reflection+questions PDF link annotation
    • https://cdn.sqhk.co/zakikola/Cie5ig4/93029975713.pdfIn PDF document text
    • https://cdn.sqhk.co/zejejofe/kijhhNe/fruit_king_produce_inc.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
    • https://33da92c3-26de-4f6b-bf12-1693cb6a6e79.filesusr.com/ugd/0307f2_1e753664ca524592956b990fdf466017.pdf?index=trueIn PDF document text
    • https://4b67404f-136a-46a0-9cf3-151f2d38faab.filesusr.com/ugd/241fd5_bf01085beb2c4a39a65b710f7eac9ae4.pdf?index=trueIn PDF document text
    • https://4cf2acc4-d143-4013-a78d-f21de0873c4f.filesusr.com/ugd/e4636f_fcfbab8e373948c5a538dce82eb1a030.pdf?index=trueIn PDF document text
    • http://pupuwifemo.rf.gd/freemake_audio_converter_er.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/01c01496-0794-4866-a1e0-3ffbf9c2b55f/how_much_does_it_cost_to_rent_a_skid_steer_with_mulcher.pdfIn PDF document text
    • https://eb40363d-1d1f-4170-a897-f23f0f433116.filesusr.com/ugd/2a1429_4f13f630c48a44b6a0bc0c40de6178ae.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/dd193db5-f451-431a-a66f-f56eaf3af4a0/what_are_the_innovative_teaching_methods.pdfIn PDF document text
    • https://36425c1f-c329-48aa-845d-1f8252cb45c8.filesusr.com/ugd/01d500_0e560d7f7f4141109ae7cd90448bfd6e.pdf?index=trueIn PDF document text
    • https://ad9e3d1f-bb22-46ca-892e-b6aa3325a756.filesusr.com/ugd/837d34_3810cf9bc84043fe990774cf13109e98.pdf?index=trueIn PDF document text
    • https://8eeb1f0a-0cdd-4c66-98a4-83777b49fb54.filesusr.com/ugd/64f9d2_bd0d8670023e47a69a501e706ff05da9.pdf?index=trueIn PDF document text
    • http://xajalad.epizy.com/59385118995.pdfIn PDF document text
    • https://5d55c623-01b0-417f-8131-8dfd0334080c.filesusr.com/ugd/9ef046_f276c43256ee4e30ac51110cfa701ff8.pdf?index=trueIn PDF document text
    • https://53002a68-e35f-4167-ac88-1ab9777d7e72.filesusr.com/ugd/f5bc2a_c54339d3be074b258d4d60301025f1d0.pdf?index=trueIn PDF document text
    • https://e3055f73-6236-423b-b810-4bc1a15f300f.filesusr.com/ugd/fa12d1_6bc696f5d7fc48f49cfbf8f8e2f9d6bd.pdf?index=trueIn PDF document text
    • https://562a32fb-e9c8-4d8f-ac7e-a760da58c396.filesusr.com/ugd/68ec97_2d89600ef50f4ab08e8e733c91653e48.pdf?index=trueIn PDF document text
    • https://deed868a-3c3f-4b0d-b3ae-f9ebe8a38c33.filesusr.com/ugd/95283b_94d50ed0f35a41d1ac61904ceed8eddb.pdf?index=trueIn PDF document text
    • https://ff743420-c5e2-4527-a456-70ddb2a1abd8.filesusr.com/ugd/5178f2_697af010125345b98cef0094dd96f1cd.pdf?index=trueIn 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_off0000f6b4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF6B4 5556 bytes
SHA-256: 9f45baa29b0a6c9aa6620935e424d9046eaa743513a5cf8a91be7815f5024afd
font_01_sfnt_off000109a2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x109A2 10920 bytes
SHA-256: 89aa2a550d74746fda322ecb577798bf07f24003e99ae148ca223ef417492070
font_02_sfnt_off00012ee4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12EE4 4324 bytes
SHA-256: 1158d95dac44631f497756703988ba3645251422e7ff0015d3fca430225e7c3e

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