Malicious PDF — malware analysis report

Static analysis result for SHA-256 cbae421ccfed84a4…

MALICIOUS

PDF

88.1 KB Created: 2021-09-22 09:23:12 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 17a6ba7e044bb8f7cb94a6d5e7320804 SHA-1: 3496f85d0fc6bd1e3709656551d5cbd72249f7dc SHA-256: cbae421ccfed84a411bc489c7bed7f4e830e50b888da19d1d5a6e1f5d0ba23c5
96 Risk Score

Malware Insights

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

The PDF file contains a link farm that directs users to multiple external websites, some hosted on compromised CMS uploads and disposable domains. The ML classifier strongly indicates maliciousness, and the structure suggests an attempt to lure users to potentially harmful content, likely as a precursor to further exploitation or phishing.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

Heuristics 5

  • 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.
  • 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://happyfun.tw/uploads/files/202109080328101853.pdf In PDF document text
    • http://aokunoil.com/ckfinder/userfiles/files/63435135323.pdfIn PDF document text
    • https://clap-bas.com/userfiles/file/21241178975.pdfIn PDF document text
    • https://www.eos.org.eg/ckfinder/userfiles/files/mebimebazubus.pdfIn PDF document text
    • http://www.olympussverige.se/wp-content/plugins/super-forms/uploads/php/files/j2o6ib0hiintmnq80a8bd42bf0/79432056115.pdfIn PDF document text
    • http://fohow77.ru/upload/file/funokiwamejaroxelilewoxol.pdfIn PDF document text
    • http://bedrucken24.de/userfiles/file/kilupumasanugukikopon.pdfIn PDF document text
    • https://smoothnomad.com/wp-content/plugins/super-forms/uploads/php/files/gb8k2e5atkgggtsql503hf3j9k/dozafekuvuzumeropoj.pdfIn PDF document text
    • https://ou-ravda.com/ckfinder/userfiles/files/90364997365.pdfIn PDF document text
    • https://doublehair.center/upload/ckfinder/files/54197116713.pdfIn PDF document text
    • https://sunriseinnjasper.com/nbloom/fckuploads/file/21300518948.pdfIn PDF document text
    • https://sonerofset.com/userfiles/file/85074595662.pdfIn PDF document text
    • https://truonggiangcompany.com/userfiles/file/62302234966.pdfIn PDF document text
    • http://0851gay.org/userfiles/202109file/2021090914285170554.pdfIn PDF document text
    • http://www.laterveer-biesenbeek.nl/ckfinder/userfiles/files/53171450781.pdfIn PDF document text
    • http://eortak.com/img/fck_temp/file/71193036174.pdfIn PDF document text
    • http://autosvilar.com/uploads/ckfinder/files/94323731468.pdfIn PDF document text
    • https://www.tzounakos-insurance.gr/ckfinder/userfiles/files/19250906986.pdfIn PDF document text
    • http://nessium.fr/userfiles/file/wesipewilumi.pdfIn PDF document text
    • https://wendi101.com/userfiles/file/11330669232.pdfIn PDF document text
    • https://textosolutionslinguistiques.ca/upload/editor/file/romokizaxavoxofabif.pdfIn PDF document text
    • http://secretinvitation.net/images/files/83359271477.pdfIn PDF document text
    • http://songdolandmarkcity.com/userfiles/file/21440136298.pdfIn PDF document text
    • http://serendipityorlando.com/wp-content/plugins/formcraft/file-upload/server/content/files/161424e3e91702---80865430034.pdfIn PDF document text
    • https://shirbandifelt.com/userfiles/file/fureso.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/FevRqgeaUVY/uplcv?utm_term=phrasal+verbs+illustrated+pdfPDF link annotation
    • 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://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f0e1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF0E1 10676 bytes
SHA-256: 64475f4382dd744fed218b601edea045cfdfc4e38e5a6a9212d04ef9092b1d1a
font_01_sfnt_off0001093e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1093E 18752 bytes
SHA-256: 4c637244af634867d9b5edda45d9bd1c5dd591ab804a5c32c935fcfa8f7fbd4d
font_02_sfnt_off00013a51.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13A51 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1