Malicious PDF — malware analysis report

Static analysis result for SHA-256 f88d57ab299e9673…

MALICIOUS

PDF

75.4 KB Created: 2021-06-22 14:32:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-16
MD5: a0fcd01aee562c59046f482b531c0a79 SHA-1: bb7b46665ef98576a3557c149a92f51637a3ea94 SHA-256: f88d57ab299e96731dcd87dde09e56838fe2fd8f57da83923d051003a8856382
164 Risk Score

Malware Insights

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

The sample is a PDF document that functions as a link farm, directing users to download other PDFs hosted on compromised websites. The ML classifier and ClamAV detection strongly indicate malicious intent, likely to deliver a phishing or trojan payload. Although no scripts were directly extracted, the PDF structure and embedded URLs suggest an attempt to trick users into downloading further malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 7

  • 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.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://www.temsilcisitesi.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608621b765006---54645607450.pdf In PDF document text
    • http://ezibra.pl/upload//file/nuvuwalujaxexu.pdfIn PDF document text
    • https://krimgranit.ru/wp-content/plugins/super-forms/uploads/php/files/170d92a1bf1a1ebca5e60f268a6d03f2/41849884655.pdfIn PDF document text
    • http://www.siscard.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606f14ddb6812---38430717198.pdfIn PDF document text
    • https://slide-bearing.com/d/files/81854404795.pdfIn PDF document text
    • https://www.bountyvacation.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608482cba7d23---4641410930.pdfIn PDF document text
    • https://www.eziblank.com/wp-content/plugins/super-forms/uploads/php/files/bkoi29vep4v9c58gb0srfh8qj4/kisukaravexanado.pdfIn PDF document text
    • http://www.consorcio.edu.pe/wp-content/plugins/formcraft/file-upload/server/content/files/1606f1121ea188---pewije.pdfIn PDF document text
    • https://sidexsideaudio.com/wp-content/plugins/formcraft/file-upload/server/content/files/16076db747a04f---jokim.pdfIn PDF document text
    • http://www.recetasyconsejos.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606cae9a9f51c---18803191353.pdfIn PDF document text
    • http://christschoolblr.in/userfiles/file/46824515993.pdfIn PDF document text
    • http://www.fliesen-brill.de/wp-content/plugins/formcraft/file-upload/server/content/files/1607075fc6d907---49302427777.pdfIn PDF document text
    • https://24emk.ru/ckfinder/userfiles/files/kutugosuwigarawan.pdfIn PDF document text
    • https://prosegik.com/wp-content/plugins/super-forms/uploads/php/files/c897f5e53ac4cd68c99504f92db988c6/mabibifitoris.pdfIn PDF document text
    • http://www.elsecretodelolivo.com/wp-content/plugins/formcraft/file-upload/server/content/files/16082fab753fa8---zedipugiweliwuvami.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/PmAiG5ZyT-k/uplcv?utm_term=mc+command+simsPDF 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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e9bb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE9BB 4960 bytes
SHA-256: 897c1b307484e7de457950ee60d18044310e22b3f242f79e719f71654efd558f
font_01_sfnt_off0000fa91.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFA91 10876 bytes
SHA-256: 331a69f03c786661f27ce8b4bbd0e0caec358ffab880840e35f0e9e633985d79