Malicious PDF — malware analysis report

Static analysis result for SHA-256 8d9ca88df1eae1e6…

MALICIOUS

PDF

84.8 KB Created: 2021-09-09 20:21:37 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 7b26d88d8639f066799a99b3316f53f8 SHA-1: f9d9084f12b981cfc366486ab552e5b7a2f38d9f SHA-256: 8d9ca88df1eae1e622117945efcdaa06231ccc29ed0378f8e8a2d61b163f2c78
156 Risk Score

Malware Insights

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

The PDF file was detected as malicious by ML classifiers and ClamAV, specifically flagged as a phishing trojan. Heuristics indicate it functions as a link farm, directing users to multiple compromised or disposable hosting sites, likely for phishing or malware distribution. The embedded URLs and the nature of the link farm suggest an attempt to exploit user trust to redirect them to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

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://efsanepin.com/calisma2/files/uploads/xilomuzosiwesiwixedasube.pdf In PDF document text
    • http://thegioichuyendong.info/app/webroot/upload/files/51614783650.pdfIn PDF document text
    • http://pusheng168.com/uploadfiles/20210904152203.pdfIn PDF document text
    • http://hart-metale.pl/gimnazjum/userfiles/file/jotatiwituxijawuvil.pdfIn PDF document text
    • http://plenar.hr/wp-content/plugins/formcraft/file-upload/server/content/files/1612fa64ddbcef---luwepegigategazux.pdfIn PDF document text
    • http://ecosdaliberdade.com/ckfinder/userfiles/files/fobipejanojowelafesotenib.pdfIn PDF document text
    • http://7sate.com/filespath/files/20210909070651.pdfIn PDF document text
    • http://www.szphotar.com/admin/img/files/66276489004.pdfIn PDF document text
    • http://olymp-kiev.com/temp/fckeditor/file/21230835160.pdfIn PDF document text
    • http://agataklimowska.pl/userfiles/file/24695408672.pdfIn PDF document text
    • http://koszyczarek.pl/userfiles/file/88265315083.pdfIn PDF document text
    • https://limblength-sldf.com/userfiles/file/1807183440.pdfIn PDF document text
    • http://gruaszarate.com/ckfinder/userfiles/files/vilubomowilakepovojeke.pdfIn PDF document text
    • http://creativecoms.net/userfiles/file/daxukinamulaz.pdfIn PDF document text
    • https://www.savininkai.lt/ckfinder/userfiles/files/tujasuxarurudovowuduvowad.pdfIn PDF document text
    • http://back2wood.de/userfiles/file/guzan.pdfIn PDF document text
    • http://prvugkh.ru/uploads/files/dotajo.pdfIn PDF document text
    • http://adoriantarla.ro/wp-content/plugins/formcraft/file-upload/server/content/files/16131af97dde70---zafekirapune.pdfIn PDF document text
    • https://wegofa.com/userfiles/file/27606307535.pdfIn PDF document text
    • https://metroguards.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1612e9e8b4b0a3---jazikujakipej.pdfIn PDF document text
    • https://szabobuszberles.hu/files/files/devupigevupulakusi.pdfIn PDF document text
    • http://detskaoptika.cz/ckfinder/userfiles/files/88567323148.pdfIn PDF document text
    • http://queensparkview.com/image/upload/File/lisibufisa.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/3vuEKuznOb8/uplcv?utm_term=clickup+app+androidPDF 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_off0000e945.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE945 10332 bytes
SHA-256: 77d95858246cb038f4aed6ea9711e387d480c979012710bc7fe27ba3185e32b2
font_01_sfnt_off0001009a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1009A 17696 bytes
SHA-256: 20bae02b9ac685d1ecc766bb6e3e925f6e6c84f5ede1346ed545059e8a8fd6a9
font_02_sfnt_off00012de2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12DE2 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1