Malicious PDF — malware analysis report

Static analysis result for SHA-256 ac139acda6901a9d…

MALICIOUS

PDF

79.8 KB Created: 2021-09-11 23:59:05 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: a21b96a453a62522644e0b9abcc5cda3 SHA-1: 5e31e9cd1ceac071e8e5d6a1c7dc5b00d9bbe84e SHA-256: ac139acda6901a9d8cb0eb15c4b386f357cea40731ceda0e8935096f54f36bd0
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to compromised websites or disposable hosting, indicating a link farm designed to redirect users. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware delivery. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic further supports the nature of the document as a link farm.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://nezrenpin.com/calisma2/files/uploads/7460011742.pdf In PDF document text
    • https://lakecountyoralsurgery.com/wp-content/plugins/formcraft/file-upload/server/content/files/16137d9ce9f533---bowetibuvifu.pdfIn PDF document text
    • https://acethamessecurity.co.uk/wp-content/plugins/super-forms/uploads/php/files/3ac30394fd0fd3174efcbc934af4861a/kexoxo.pdfIn PDF document text
    • https://mercerapparelss.com/userfiles/files/xojanat.pdfIn PDF document text
    • http://queuemanagementsystems.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613164d158de6---kutafosesab.pdfIn PDF document text
    • http://sanitaerprofi.ch/fckeditor/editor/images/file/56896710378.pdfIn PDF document text
    • http://321eastern-thailand.com/userfiles/files/69332802975.pdfIn PDF document text
    • http://d-a-s.cn/userfiles/file/1673037887.pdfIn PDF document text
    • http://aromaonly1.com/yamituki-n/uploads/files/pakiterujeximag.pdfIn PDF document text
    • http://posicert.com/upload_fck/file/2021-9-5/20210905065835725563.pdfIn PDF document text
    • https://condicionamentofisico.com/arquivos/file/wonemede.pdfIn PDF document text
    • https://chingchia.com/uploads/files/202109110645131693.pdfIn PDF document text
    • http://www.kizkulesikizogrenciyurdu.com/public/ckfinderuploads/files/19657411258.pdfIn PDF document text
    • http://bagodilovaspark.hu/userfiles/file/suxibu.pdfIn PDF document text
    • http://vip-cond.ru/userfiles/file/16549422646.pdfIn PDF document text
    • https://thehamptonsbloomington.com/wp-content/plugins/formcraft/file-upload/server/content/files/161374ef7c98cf---26738098856.pdfIn PDF document text
    • http://bradzo-ep.com/uploads/files/27891143696.pdfIn PDF document text
    • http://banquat.com/userfiles/files/redovaxapu.pdfIn PDF document text
    • http://studio5r.com/userfiles/files/sekivufewo.pdfIn PDF document text
    • http://jedzenie365.pl/ckfinder/userfiles/files/35811553502.pdfIn PDF document text
    • http://posuni.com/userfiles/file/baritejekomafumibif.pdfIn PDF document text
    • https://sharzh-ufa.ru/wp-content/plugins/super-forms/uploads/php/files/07af88f1addb5de41ebd3b71d1045b16/58796648521.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/1KS0DP0cxss/uplcv?utm_term=physical+biology+of+the+cell+2nd+edition+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_off0000d083.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD083 11176 bytes
SHA-256: 3d01fee7cd720400b0443db946884b0c4ebae64aff2956aa2ceb9017793a99fe
font_01_sfnt_off0000ea49.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEA49 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0001025b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1025B 18164 bytes
SHA-256: f4b8913ce24d5b86cb7dab68c1a39c1fed3c3eaa62cc868b0e54f32cef00fc31