Malicious PDF — malware analysis report

Static analysis result for SHA-256 853f864e09d2b22c…

MALICIOUS

PDF

84.0 KB Created: 2021-09-15 20:01:57 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 151538bc18d619e75ac6cc1609357cbc SHA-1: 88135b88df14701d626351da775db397e6dfe5bc SHA-256: 853f864e09d2b22cb67b6c6453482c462eb4773f5015b18a7c4e2ebbd1d0f304
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to disposable hosting or compromised CMS upload directories, indicating a link farm designed to distribute malicious content. The ML classifier and ClamAV detection strongly suggest malicious intent, likely related to phishing or malware delivery. The document body is heavily obfuscated and unreadable, providing no direct clues to its purpose beyond the heuristic findings.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://synerhu.ru/uplcv?utm_term=forecast+android+app PDF link annotation
    • http://qianshunqs.com/admin/upload/64751988608.pdfIn PDF document text
    • https://sharkovinkom.com/sharkovinkom.com/ckfinder/userfiles/files/gilofapugalawajoxomuxim.pdfIn PDF document text
    • http://kazenergy.kz/wp-content/plugins/formcraft/file-upload/server/content/files/1613ec04fcb049---64709402208.pdfIn PDF document text
    • https://vzglavniki.net/data/file/juridirapufeximolukurisov.pdfIn PDF document text
    • http://happinessgown.com/upload/users/files/gaturepewurijo.pdfIn PDF document text
    • http://ceomit.com/fckupload/file/jogexojixalabubo.pdfIn PDF document text
    • https://neurondevelopment.org/userfiles/file/37051119253.pdfIn PDF document text
    • http://pro-elec.ru/ckfinder/userfiles/files/wuxatozo.pdfIn PDF document text
    • https://enilubricantvn.hoakhanh.vn/uploads/image/files/botofotomisi.pdfIn PDF document text
    • https://www.dogandemir.av.tr/paketler/ckfinder/dosyalar/files/6766890835.pdfIn PDF document text
    • http://smingames.com/ckfinder/files/67048675504.pdfIn PDF document text
    • http://grupophi.es/uploads/files/kajasek.pdfIn PDF document text
    • http://www.holzbau-hoelzl.at/wp-content/plugins/formcraft/file-upload/server/content/files/16136f9e8af455---69420672551.pdfIn PDF document text
    • http://01host.ru/userfiles/files/4410511775.pdfIn PDF document text
    • http://maremania.net/img_pagine/file/sogaxavase.pdfIn PDF document text
    • http://htwy.com/upload/file/69818949414.pdfIn PDF document text
    • http://axi-hohenstein.de/userfiles/file/midox.pdfIn PDF document text
    • http://metrominicabs.com/survey/userfiles/files/bumijama.pdfIn PDF document text
    • http://bidwoodmachine.com/d/files/gobogevev.pdfIn PDF document text
    • https://www.techsrollout.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613791af28268---rorokevubipofowifenu.pdfIn 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://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_off0000e6b9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE6B9 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000fed0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFED0 10440 bytes
SHA-256: 058fb7baf355487f2e4c08b3977fd665ff62c5c0dc32df6c15bf234b065cf5ff
font_02_sfnt_off00011691.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11691 17180 bytes
SHA-256: 2d8875f10bae8c546f7473fffb91759b46cb75fbc6a4d353dd8294bae465f3a8