Malicious PDF — malware analysis report

Static analysis result for SHA-256 91c61e64726dc844…

MALICIOUS

PDF

80.8 KB Created: 2021-06-18 01:34:17 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-07
MD5: ff089129a41a92be9f42a245f809b420 SHA-1: 929ad87a9c9de24400a41401472d2905c7f14f5b SHA-256: 91c61e64726dc844afa8deafbd3d039be4a1a10a9d8b05973d7d3debeb61fd83
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The PDF document contains numerous links to external websites, many of which are hosted on compromised WordPress sites, suggesting a link farm or phishing campaign. The ML classifier and ClamAV detection strongly indicate malicious intent. The document body, though heavily obfuscated, contains references to 'wkhtmltopdf' and 'compress pdf file', aligning with the heuristic findings of PDF link farms and compromised CMS uploads, likely serving as a lure to malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://crysiq.ru/uplcv?utm_term=compress+pdf+file+to+200kb+online+free PDF link annotation
    • http://www.sarajevo-inn-grunewald.com/wp-content/plugins/formcraft/file-upload/server/content/files/160843432ec224---xefimumoman.pdfIn PDF document text
    • https://advicezone.org.uk/wp-content/plugins/super-forms/uploads/php/files/pr0bi1apojbofbnpil7q4kslu0/29946198359.pdfIn PDF document text
    • https://goldenapp.net/file/wijikeni.pdfIn PDF document text
    • https://luxmarketing.agency/wp-content/plugins/super-forms/uploads/php/files/tuo2bku839cc2su9m119ahs02u/21077256176.pdfIn PDF document text
    • https://imapcb.org/wp-content/plugins/super-forms/uploads/php/files/s1b6k16sev4bue6kmu96dj8ra0/34872994623.pdfIn PDF document text
    • https://erinmillssmilesdentistry.com/wp-content/plugins/super-forms/uploads/php/files/g0cvahltcvqcski4lqvols39e7/47778749526.pdfIn PDF document text
    • http://euro520.net/userfiles/file/16213383591417397901.pdfIn PDF document text
    • http://themultifold.com/wp-content/plugins/super-forms/uploads/php/files/cde7mp8715g6pcocknt32ulmo0/vipowopolanoko.pdfIn PDF document text
    • http://sumnerclassof1976.com/clients/4/49/49b54eafcc86ae0c30eb104ab8b91c7c/File/2475127659.pdfIn PDF document text
    • https://leunamgroup.com/wp-content/plugins/super-forms/uploads/php/files/320ed5a7047d2c629eb584c5f512e0b7/zabokebomotezowukudulosir.pdfIn PDF document text
    • http://10glazsikeyrosa.ru/file/goxaveramutimaru.pdfIn PDF document text
    • http://skup-laptopow.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608ad0a8939c8---sunodajipapilivaz.pdfIn PDF document text
    • http://projectbudapest.hu/wp-content/plugins/formcraft/file-upload/server/content/files/160858f16a3bb8---53617471244.pdfIn PDF document text
    • http://lorofilmes.com/Uploads/ckfinder/userfiles/files/jefapilovisubadavutokow.pdfIn PDF document text
    • http://conservationenergy.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b0052a03cdd---81007354910.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://www.daltonmaag.com/In 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f02d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF02D 5264 bytes
SHA-256: 4d03611b4003e8f421ca7b70331995f79da28acde23e13cdcf23be50decfbf03
font_01_sfnt_off000101f6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x101F6 11156 bytes
SHA-256: f447cae761b4219e1b0ea9a1f4e24a382878591fcf842c6c9b9cbaa3bccbe7e7
font_02_sfnt_off000127c4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x127C4 4324 bytes
SHA-256: ff5f0ef16caf3e97cd1984b3a03ea88e11eab8cf63d2ee006085a4b9995833f3