Malicious PDF — malware analysis report

Static analysis result for SHA-256 dc636dbb1fafb8cc…

MALICIOUS

PDF

95.1 KB Created: 2021-09-14 08:24:10 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 89608f234c16c35d692e1f99ff3976ff SHA-1: 74f979e6dc67901e65600fc4b1465e5f2e5e04fe SHA-256: dc636dbb1fafb8cc126a1135692cdbde0771d01d71076591de43b429e8651a3e
96 Risk Score

Malware Insights

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

The ML classifier strongly indicated maliciousness, and heuristics identified the PDF as a link farm. Several URLs point to PDF files hosted on what appear to be compromised CMS upload directories or disposable hosting. The primary function seems to be redirecting users to other malicious or SEO-manipulated content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9929

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 http://onsijsselstein.nl/userfiles/files/kimefunufami.pdf In PDF document text
    • http://chuabenhxuongkhop24h.com/images/files/68183249003.pdfIn PDF document text
    • http://quranday.org/userfiles/file/39249957899.pdfIn PDF document text
    • https://riosemarescentrodemergulho.com/ckfinder/files/40986914044.pdfIn PDF document text
    • https://lexcyberia.com/userfiles/files/sevezimufefezexivaku.pdfIn PDF document text
    • http://dinskayarealty.ru/media/file/43664289114.pdfIn PDF document text
    • https://littleedupark.com/ckfinder/userfiles/files/titurodajizuru.pdfIn PDF document text
    • http://voszveszprem.hu/_user/file/jojasinawomax.pdfIn PDF document text
    • http://anhbanglaw.com/userfiles/file/25801480193.pdfIn PDF document text
    • http://hanasushichoice.com/uploads/files/girelogotazabuv.pdfIn PDF document text
    • https://www.adler-leitishofen.de/wp-content/plugins/formcraft/file-upload/server/content/files/1613bc628396fd---69606194467.pdfIn PDF document text
    • http://bbdecontra.com/userfiles/files/soxosamofage.pdfIn PDF document text
    • https://dennismaloney.ca/upload/editor/file/darizoxusadesel.pdfIn PDF document text
    • https://stancijanegrin.com/UserFiles/files/49789072903.pdfIn PDF document text
    • https://mzr-avocats.com/buddha/ckfinder/userfiles/files/miboxajedumegilorop.pdfIn PDF document text
    • http://machin.kr/userData/board/file/meguxigerawami.pdfIn PDF document text
    • https://sunarchegypt.com/userfiles/file/nirusotila.pdfIn PDF document text
    • http://sklepjola.pl/userfiles/file/kefome.pdfIn PDF document text
    • http://pololanna.com/user_img/files/80847809443.pdfIn PDF document text
    • http://risme.vn/files/43578923805.pdfIn PDF document text
    • http://fongyoskert.hu/userfiles/files/47499528906.pdfIn PDF document text
    • http://grupomarsamo.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613b3fd302309---xebuduzajedefa.pdfIn PDF document text
    • http://autolubitel-irk.ru/userfiles/file/soferakobupaz.pdfIn PDF document text
    • https://www.lorenzofranzone.it/wp-content/plugins/super-forms/uploads/php/files/14d39f11d7fb437903388266a545386c/gawuperiwivotadomi.pdfIn PDF document text
    • https://aftaplan.com/works/peepsparty/html/upload_files/file/vabosojabo.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/BkSY9tpko7c/uplcv?utm_term=gomovies+the+flashPDF 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_off0001133c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1133C 17220 bytes
SHA-256: 41e4691776418c005acd8d10680cc1ed0335db69b4c51b5c7846ef792b58d270
font_01_sfnt_off00013f90.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13F90 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000157a7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x157A7 10380 bytes
SHA-256: 83230ab17ec64e3712f89a584cf1742101c89090dde918a83a08f618788d2097