Malicious PDF — malware analysis report

Static analysis result for SHA-256 7839018f0c78d72c…

MALICIOUS

PDF

84.6 KB Created: 2021-07-16 06:05:00 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 636f1ffab5ea75c6b222715d812a29c2 SHA-1: 4690f85184670d26ba2547090c16aa3e31fbc717 SHA-256: 7839018f0c78d72cb7ba4a5574bb5b9f57c39a68d7973785ee8e75dac23b977d
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous links to other PDF files hosted on compromised websites, indicating a link farm likely used for SEO poisoning or to distribute further malicious content. The ML classifier strongly flagged this PDF as malicious, and heuristics identified it as a link farm on disposable hosting and pointing to compromised CMS uploads. No scripts were extracted, but the structure suggests a malicious document intended to redirect users to potentially harmful content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

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://hashtag.school/userfiles/file/861730821.pdf In PDF document text
    • https://medtek.vn/storage/file/82559399563.pdfIn PDF document text
    • https://specialbrands.gr/wp-content/plugins/super-forms/uploads/php/files/85ef6de337afe2f150d9b633cab94dfa/pavamiluj.pdfIn PDF document text
    • https://sckprime.com/wp-content/plugins/super-forms/uploads/php/files/a9716c6a713fca12e9be085a4c7e267f/bumuputidezerivuletifa.pdfIn PDF document text
    • https://dtcprojects.com.au/wp-content/plugins/super-forms/uploads/php/files/g83md1c3a3t3d2ijmvi3la5nf9/nulubusavemebagubirakosug.pdfIn PDF document text
    • https://birotex.rs/images/files/fusonutupesef.pdfIn PDF document text
    • http://nothingelsematters.net/pharma/images/files/16838333567.pdfIn PDF document text
    • http://www.siscard.com/wp-content/plugins/formcraft/file-upload/server/content/files/16087e48b0c4c4---ganex.pdfIn PDF document text
    • https://www.alongsideasia.com/wp-content/plugins/super-forms/uploads/php/files/41bb76ef7d31256e09ed3ffb1e08f16a/16255430617.pdfIn PDF document text
    • http://barcelonasixtytwo.com/userfiles/file/21005158551.pdfIn PDF document text
    • http://marketypik.pl/zdjecia/fck/file/36799317156.pdfIn PDF document text
    • https://orkhaconstruction.com/wp-content/plugins/super-forms/uploads/php/files/e4vhs24prmt061cb1bjaaeok7g/64584045158.pdfIn PDF document text
    • https://pluviaterra.mx/wp-content/plugins/super-forms/uploads/php/files/9773141ce8a620ced9538291df9300f2/34072541098.pdfIn PDF document text
    • http://gomientrung.vn/uploads/image/files/mipexexewixivatatilabow.pdfIn PDF document text
    • http://cityhelps.org/clients/6/61/61afa7a028a8e04f14432b0fece6f2b0/File/mavapitudepisikireri.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3vuEKuznOb8/uplcv?utm_term=outbound+sales+strategyPDF 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_off0000e8b0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE8B0 16980 bytes
SHA-256: 105264eddad35d02d04bb277d5d545073047a5e5cdbed545c0d454a105294d9d
font_01_sfnt_off00011526.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11526 10712 bytes
SHA-256: f7fdcc2277c86b7efd75051233a410d25855f861462b2734cf18fded82248585
font_02_sfnt_off00012dc2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12DC2 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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