Malicious PDF — malware analysis report

Static analysis result for SHA-256 131f75ec2b4b5b96…

MALICIOUS

PDF

70.7 KB Created: 2021-04-19 16:14:53 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-23
MD5: b9d346ffead1f536ba07ab01d7d1a4df SHA-1: de21a83994f97f986d254ec6387e79888908f320 SHA-256: 131f75ec2b4b5b96213ea5457f76d7a0f648fd350aa006dfc79260e941d27318
186 Risk Score

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 a large number of external links, many pointing to disposable domains, suggesting a link farm used for phishing or malware distribution. The document body, though heavily obfuscated, contains references to 'wkhtmltopdf' and 'dna replication practice worksheet pdf', indicating a lure to disguise the malicious intent. No scripts were extracted, but the PDF structure itself facilitates the redirection to malicious URLs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

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://jumiwimov.ru/strik?utm_term=dna+replication+practice+worksheet+pdf PDF link annotation
    • http://uspex22.online/what_were_the_two_plans_for_reconstruction_that_were_usedu8wwk.pdfIn PDF document text
    • http://poverkavoda.website/que_es_el_ayuntamiento_en_la_biblialpfdh.pdfIn PDF document text
    • http://portkamesto.site/boku_boku_lyricsadxt9.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://4cf6c2b4-cd84-4b73-83b1-bf7f441162b2.filesusr.com/ugd/e50c99_099b8a2d8f63454889f2021794f39a9b.pdf?index=trueIn PDF document text
    • https://e216d865-ddc7-438b-99b2-64609380b1bb.filesusr.com/ugd/7ae8b3_5d9db683210f4afa9b82bdbf4da102a1.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/353e91bb-f9d9-44cb-9321-6c7cf241da94/jarikinepapadevi.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/ba58b08f-9ff8-4aaa-be0e-38d3d37dcdb3/ropaputozetirijofexapem.pdfIn PDF document text
    • http://rurubafemiw.rf.gd/pipigalovus.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/b4dcd486-d3d5-43de-890c-bb85978ad700/how_to_bypass_motion_sensor_light.pdfIn PDF document text
    • http://lagorov.rf.gd/famugewigamogijag.pdfIn PDF document text
    • https://7c50ec62-1ece-451b-b03c-4788199016cf.filesusr.com/ugd/635f3c_8a31aa86305249998272ce00ab10156b.pdf?index=trueIn PDF document text
    • http://vekalaluno.epizy.com/14780931296.pdfIn PDF document text
    • https://2e907eb7-0cdb-46e5-a4de-ff0e34d1b96e.filesusr.com/ugd/7ea2c5_8facca0346b24fe48ad7f8b4acba1bc4.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/6a189ced-c4ea-4ef0-9911-124b114c0c3c/loseit_healthometer_scale.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/33bdb631-c34b-4184-951c-7a0cf88cbe7a/citizen_eco_drive_gn-4w-s-12g_manual.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/5da7a5b4-776f-457d-a463-e58c41c2b4ad/nolada.pdfIn PDF document text
    • http://pirutipubik.epizy.com/ponegugusofukupilavefuzi.pdfIn PDF document text
    • https://9334512a-4df1-45dc-8804-f0fa1d9e2a3d.filesusr.com/ugd/9466eb_c114c841274b49218d8d98a22656e5c8.pdf?index=trueIn PDF document text
    • https://caf0f927-206f-4b4e-aa34-0dd3da53679b.filesusr.com/ugd/83d902_1959c35e83af4147878700560f9c25de.pdf?index=trueIn PDF document text
    • http://rujewaridulev.rf.gd/funijebewoxeded.pdfIn PDF document text
    • https://4f7f339c-9ee9-4921-a7ad-794169edd555.filesusr.com/ugd/fea72b_37e73f4b232643958c91f82cf3604a04.pdf?index=trueIn PDF document text
    • https://2559d30b-64cd-4b4d-aaad-e76a675dde99.filesusr.com/ugd/f5a024_0d2986493fd24aac92eeaeb8e49dd456.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/c1272d6b-c64a-4070-8c5d-8200c9b29be2/twilight_movie_2012_download_in_hindi_filmyzilla.pdfIn PDF document text
    • https://68f2566a-c586-4d15-a5d1-3a72044c38f3.filesusr.com/ugd/ecec20_2a01b34c310a4ab78f6e42e003addd3b.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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d7a9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD7A9 5396 bytes
SHA-256: 9cafe3613d5f93e8118c2b578a236a29bc1ae0548a55c7aa150615ace12a92bf
font_01_sfnt_off0000ea18.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEA18 10156 bytes
SHA-256: 1fb3a6e4b103a46475ba170cd5c8b6da01aed51292d412fdf9304fc70bd74a6c

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