Malicious PDF — malware analysis report

Static analysis result for SHA-256 3dcb8e1d6fd2f1c9…

MALICIOUS

PDF

87.2 KB Created: 2021-09-10 18:25:41 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: ecbf23cd7db739168d7dd07fad3022bb SHA-1: 929f78e2e0b4b11b815ecebca02dc6446487cb02 SHA-256: 3dcb8e1d6fd2f1c9be1394fe46f604e53c43508f282b1aa6d83a271ecb07727f
156 Risk Score

Malware Insights

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

The file is identified as malicious by ML classifiers and ClamAV, indicating it's a phishing or trojan PDF. It functions as a link farm, with numerous embedded URLs pointing to compromised WordPress sites and other domains, likely to lure users to malicious content. The presence of external URI heuristics and link farm indicators strongly suggests an attempt to redirect users to potentially harmful sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9912

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://sk-developers.com/wp-content/plugins/formcraft/file-upload/server/content/files/16138c8219a567---deloraropaxeninijag.pdf In PDF document text
    • http://kowel.com/ckfinder/userfiles/files/1631182431.pdfIn PDF document text
    • http://forspeed.cz/ckfinder/userfiles/files/vajalomenafatarimoxifat.pdfIn PDF document text
    • http://bibliotekaludwin.pl/img/upload/files/neleterejodives.pdfIn PDF document text
    • http://mmbc.cz/_data/user_files/file/10783047893.pdfIn PDF document text
    • https://praktijk.zorglink.nl/ckfinder/userfiles/files/xelezatafoto.pdfIn PDF document text
    • http://smart-ventures.ch/upload/Editor_Images/files/53269658764.pdfIn PDF document text
    • http://chiangmaicharmingtravel.com/ckfinder/userfiles/files/99391105256.pdfIn PDF document text
    • http://brilliantsolarpaneling.com/userfiles/file/79721108658.pdfIn PDF document text
    • http://stopasbestos.ca/wp-content/plugins/formcraft/file-upload/server/content/files/16132c0018aa7d---14273937519.pdfIn PDF document text
    • https://duvarkagidierzincan.com/userfiles/file/jitekegazetazigud.pdfIn PDF document text
    • http://mojahotels.com/ckfinder/userfiles/files/tizekesinesupur.pdfIn PDF document text
    • http://ipceurope.eu/assets/file/37108105904.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613000e5b1c85---53968694343.pdfIn PDF document text
    • https://stellabakingcompany.com/wp-content/plugins/formcraft/file-upload/server/content/files/16130ca83ab5ea---notulurifopap.pdfIn PDF document text
    • http://htwy.com/upload/file/74739693960.pdfIn PDF document text
    • http://pnmanagementsolutions.in/uploads/vodisifaranoronekada.pdfIn PDF document text
    • http://liavanhaeringen.nl/userfiles/files/foxeteravedalawu.pdfIn PDF document text
    • http://www.bash.cl/media/file/57717542200.pdfIn PDF document text
    • http://sochi-polyana.com/ckfinder/userfiles/files/62058179590.pdfIn PDF document text
    • http://architettoseneca.com/userfiles/files/regevividotubazif.pdfIn PDF document text
    • http://le-nora.com/userfiles/file/warolidilorigufojalow.pdfIn PDF document text
    • http://woonhuislift.info/wp-content/plugins/formcraft/file-upload/server/content/files/1613187b4237e0---fimojafaxazosuteno.pdfIn PDF document text
    • http://kamnitikamini.si/upload/files/mubanub.pdfIn PDF document text
    • https://gamletaarnhuset.no/wp-content/plugins/formcraft/file-upload/server/content/files/161324d15db90d---53194764954.pdfIn PDF document text
    • http://clairerolo.com/userfiles/file/memebogot.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/LPIa9PGmDLg/uplcv?utm_term=how+to+install+apk+on+chromebook+without+developer+modePDF 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_off0000ea43.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEA43 19432 bytes
SHA-256: baec2e8b771a586d28856934511f703371b13e1b59feab1c752f3efb010560af
font_01_sfnt_off00011c68.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11C68 11256 bytes
SHA-256: 6f82b493ecb5dafaa23c080b93c574ee3ac558f8c4fdf19b4b2007c71f3f6866
font_02_sfnt_off0001366c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1366C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1