Malicious PDF — malware analysis report

Static analysis result for SHA-256 c6b3cf5ce384f5fa…

MALICIOUS

PDF

81.2 KB Created: 2021-06-14 06:16:15 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-26
MD5: ef361fa9085b825910560a3a9aa08d54 SHA-1: aaca8469ee598bbad5d2623000f3299ca216920c SHA-256: c6b3cf5ce384f5fab0c794126e0db05b954ca1bcc4487bd1bc90fd8b81bc7187
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains a large number of external links, many of which point to websites hosted on compromised CMS platforms or disposable domains. The ML classifier strongly indicated maliciousness, and the link farm behavior suggests an attempt to manipulate search engine results or direct users to potentially harmful content. No scripts were extracted, and the document body was heavily obfuscated.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://infrive.ru/uplcv?utm_term=examen+diagnostico+de+ingles+para+primaria+pdf PDF link annotation
    • http://takeacode.eu/user/d41d8cd98f00b204e9800998ecf8427e/file/45165299083.pdfIn PDF document text
    • http://discoveryenglish.org/wp-content/plugins/formcraft/file-upload/server/content/files/16073864cb10fc---rovexusubivamoseso.pdfIn PDF document text
    • https://www.mnspineandsport.com/wp-content/plugins/super-forms/uploads/php/files/97cfab22210fda5627a664f6b15fd47a/59045562352.pdfIn PDF document text
    • https://shining4u.com/wp-content/plugins/super-forms/uploads/php/files/1f807fd2efa59778297514a86d50193d/sufomazutewapujig.pdfIn PDF document text
    • https://impariant-club.ru/wp-content/plugins/super-forms/uploads/php/files/73578ac017c6cb8e08187752f5d25bdd/vavabalakiwejepa.pdfIn PDF document text
    • http://for-rent-antwerp.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609f62b3d5694---10197298238.pdfIn PDF document text
    • http://malbreil.com/userfiles/file/82748708516.pdfIn PDF document text
    • http://www.pattyn360.com/upload/forum/files/28900794477.pdfIn PDF document text
    • http://fitsiluet.cz/data/file/99388995232.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/16091cc8cdb4ff---74998066916.pdfIn PDF document text
    • http://permianhighschool1970.com/clients/e/ef/efee9fcbc667252fc4b649c8163d3733/File/43366640543.pdfIn PDF document text
    • https://bykevin.com/wp-content/plugins/super-forms/uploads/php/files/812a16e6899ea2c24d55605cbe7a1e0f/35257898657.pdfIn PDF document text
    • https://victory-agency.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609df075013d4---kipiletiborariwutugivu.pdfIn PDF document text
    • https://all-stage-meditation.tw/uploads/files/60b7c014d21fc.pdfIn PDF document text
    • http://www.sarajevo-inn-grunewald.com/wp-content/plugins/formcraft/file-upload/server/content/files/160900cfc47dab---gagatomawezadodakilofo.pdfIn PDF document text
    • http://ahdongjiu.com/upload_fck/file/2021-5-12/20210512102817394720.pdfIn PDF document text
    • https://dbjadow.pl/attachments/file/64079087427.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn 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_off0000fc2a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFC2A 5500 bytes
SHA-256: fa7fd833ad67ac3576cc8ef879950b94937f2b2280e1218360b01be3f833b13c
font_01_sfnt_off00010ed5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10ED5 12108 bytes
SHA-256: d43a312e22e6bc03415d40c7288937e353faba117a1386e26f9089b5c05b6fcc