Malicious PDF — malware analysis report

Static analysis result for SHA-256 5c85f0c9420658ae…

MALICIOUS

PDF

77.9 KB Created: 2021-06-18 04:18:30 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-25
MD5: 83aaf909895c0e53892ad5551e350748 SHA-1: a19b1563fb7836dbcb9b1ac6a45430106529375e SHA-256: 5c85f0c9420658aedbee31a8b630bac84cc2f0489c5cf77fbd5f2970b68b94a5
156 Risk Score

Malware Insights

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

The PDF contains numerous links pointing to compromised WordPress upload directories, indicating it functions as a link farm. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for phishing or distributing further malware. The document body is heavily obfuscated and unreadable, providing no direct clues to its specific purpose beyond the link farm heuristic.

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://bokseinstituttet.dk/wp-content/plugins/formcraft/file-upload/server/content/files/160a82157e84df---xaboxekepowogabiwamixib.pdf In PDF document text
    • https://www.elektrobetrieb-scholz.de/wp-content/plugins/formcraft/file-upload/server/content/files/160983dd5daa69---53825870430.pdfIn PDF document text
    • http://www.wallisandemmanuel.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606f26490019a---4552824594.pdfIn PDF document text
    • http://gorisum.net/fckeditor/upload_file/file/gegumosi.pdfIn PDF document text
    • http://bezagsecurity.cz/userfiles/kalifazumuxividox.pdfIn PDF document text
    • https://agsposure.org/wp-content/plugins/super-forms/uploads/php/files/7e5911f524d9706056778e6e86bd575f/tegita.pdfIn PDF document text
    • https://xn----7sbabak5acz7byau.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/409ba03adc17e8af9bd2098c70c7bd13/85841986212.pdfIn PDF document text
    • https://www.avenueroadadvertising.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a06276012ce---24186371107.pdfIn PDF document text
    • https://bestmiamiturf.com/wp-content/plugins/super-forms/uploads/php/files/20957e34a68ba495be99c7a3df1839d8/61348086818.pdfIn PDF document text
    • https://acronimocostanzo.com/userfiles/file/lumijazokipo.pdfIn PDF document text
    • http://tradeweb.es/userfiles/file/jujonobisov.pdfIn PDF document text
    • https://efnnma.org/files/file/21029945060.pdfIn PDF document text
    • https://avis-medical.ma/wp-content/plugins/super-forms/uploads/php/files/a108a242367c6bc40f792688692e7562/xanolowika.pdfIn PDF document text
    • https://gz-topstar.com/wp-content/plugins/super-forms/uploads/php/files/77c5a932f67d6fe01aa502642571e54e/zabevadajodiko.pdfIn PDF document text
    • https://homini.eu/wp-content/plugins/formcraft/file-upload/server/content/files/16089a3937a915---57779962236.pdfIn PDF document text
    • https://blindnow.com/userfiles/file/pifoxufubovuz.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/~3/6naE_Nh8_CY/uplcv?utm_term=aot+english+dub+season+4PDF 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_off0000eddc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEDDC 5208 bytes
SHA-256: ee57126677e0abd258dcffe5744ec7581754a167721d29ccb3d783f52e4e40c3
font_01_sfnt_off0000ff95.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFF95 12592 bytes
SHA-256: b041e6275e1e11666adb5702972acad2a289a8a257c382a8fbe39403ca2bd8e9