Malicious PDF — malware analysis report

Static analysis result for SHA-256 d88fc5ac62bb550d…

MALICIOUS

PDF

83.6 KB Created: 2021-06-26 01:05:40 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-08-20
MD5: 91f4aa9b2518e03e82c6e19067a1dc14 SHA-1: 95cb3fadf81781e9f8b6720c0492e56362cdc43c SHA-256: d88fc5ac62bb550dd933593f14b0064fb0ab7779961d668f266cfe0fdbf021ac
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous links, many pointing to compromised WordPress sites and disposable hosting, suggesting a link farm for SEO manipulation or to distribute further malware. The ML classifier strongly indicates maliciousness. No scripts were extracted, but the structure and URL patterns are indicative of a malicious document, likely delivered via spearphishing.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9964

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://vantaibactrungnam.vn/upload/files/ralirororuliviw.pdf In PDF document text
    • https://abofahed.com/userfiles/file/suxarux.pdfIn PDF document text
    • http://drthchowdary.net/userfiles/file/67984324556.pdfIn PDF document text
    • https://evenimentecastel.ro/wp-content/plugins/super-forms/uploads/php/files/plr12t1j7aj361lhilcuakukck/80943129314.pdfIn PDF document text
    • https://refour.dk/wp-content/plugins/super-forms/uploads/php/files/77311050b19dcece0f52f6fe7c5f9a20/29429063874.pdfIn PDF document text
    • https://thejasmineway.net/wp-content/plugins/super-forms/uploads/php/files/k2f5sdmjobsjsfjhls73au5s76/javeranegavesupugiboxates.pdfIn PDF document text
    • http://bestapp4u.com/admin/uploadedfiles/file/80505397299.pdfIn PDF document text
    • http://www.rebranded.tv/wp-content/plugins/formcraft/file-upload/server/content/files/16080ec26c8061---3142911236.pdfIn PDF document text
    • http://adhdadvisory.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608c2b0888d9d---xumirijagugopetodurabepu.pdfIn PDF document text
    • https://www.dynasil.com/wp-content/plugins/super-forms/uploads/php/files/3219ce7aa9ea9d4de0befee1403205d6/63586718075.pdfIn PDF document text
    • http://www.nuricomuvakfi.org/wp-content/plugins/super-forms/uploads/php/files/4oslkrf9ubfi728qfo621pnnp2/rigudasiguborokasujep.pdfIn PDF document text
    • http://dabaizhongxue.com/upload_fck/file/2021-5-14/20210514132226349319.pdfIn PDF document text
    • https://www.temsilcifirsatlari.com/wp-content/plugins/formcraft/file-upload/server/content/files/16085df5db1360---69434342082.pdfIn PDF document text
    • https://hanahana.vn/media/ftp/file/89375862056.pdfIn PDF document text
    • http://shethof.ch/cgi-bin/dynamisch/file/49542828756.pdfIn PDF document text
    • http://hnspkjx.com/d/files/nexujemugebonoxifizavav.pdfIn PDF document text
    • http://redwoodpwr.com/wp-content/plugins/super-forms/uploads/php/files/lgg6dn4oios9dmorhas6dj4gn5/37918622704.pdfIn PDF document text
    • https://gastriklandsbf.se/UserFiles/files/27030239755.pdfIn PDF document text
    • http://www.derbysignandgraphics.com/uploads/file/vexofedotexenubimovojuriw.pdfIn PDF document text
    • http://www.alfainstal.pl/wp-content/plugins/formcraft/file-upload/server/content/files/1608f93ccf1c0f---84638358849.pdfIn PDF document text
    • https://coachtourbusrental.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b0a982611de---17447040597.pdfIn PDF document text
    • http://fsoa.cn/userfiles/file/39982076498.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/Om9ozkHLxGw/uplcv?utm_term=funny+unicorn+coloring+pagesPDF 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_off0000e48b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE48B 17172 bytes
SHA-256: a53404ac4d4100902e2c651dcd45ef7765492493857f23d302a2a054d7a7ea86
font_01_sfnt_off000110fc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x110FC 10644 bytes
SHA-256: 555378d3d44f5ba78b0638c13a534b698411485d16e5656e8059fa54b09c869e
font_02_sfnt_off0001297a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1297A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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