Malicious PDF — malware analysis report

Static analysis result for SHA-256 836b9520184c5259…

MALICIOUS

PDF

82.0 KB Created: 2021-09-03 22:51:07 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: a5e15c39e8d9fffe0c656e5e704c0b9e SHA-1: 2638471b244b701d41598ada08c5d01964a79a34 SHA-256: 836b9520184c52599048104c735b35d9a969c7662c516483a10f78acd079727e
196 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous links to external websites, many hosted on compromised CMS uploads or disposable domains, indicating a link farm designed to redirect users. The ClamAV detection and ML classifier strongly suggest malicious intent, likely for phishing or distributing further malware. No scripts were extracted, but the presence of external links points to an initial access vector via spearphishing attachment.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9964

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 to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://crewmak.ru/uplcv?utm_term=great+quotes+of+all+time+pdf PDF link annotation
    • https://vinisfarm.com/wp-content/plugins/super-forms/uploads/php/files/0af0c97587d202b0cff75cbb9fe50e3e/watovuvibuvozisasamugef.pdfIn PDF document text
    • https://www.phoenixdentalacademy.co.uk/wp-content/plugins/super-forms/uploads/php/files/2a267229aa620a9620e1e84c2ae2c990/45831048314.pdfIn PDF document text
    • http://conservationenergy.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a9c00e8c05c---12496184287.pdfIn PDF document text
    • http://www.pattyn360.com/upload/forum/files/goriwuramenexi.pdfIn PDF document text
    • https://blackknowledge.com/wp-content/plugins/super-forms/uploads/php/files/0fb4b5456b8d5e233faa915b9f36ac51/14942778563.pdfIn PDF document text
    • https://frasertechno.com/wp-content/plugins/formcraft/file-upload/server/content/files/16076fd133c9ab---69747148836.pdfIn PDF document text
    • http://tele-fonika.pl/upload/file/90654852220.pdfIn PDF document text
    • https://www.certificagreen.com/wp-content/plugins/formcraft/file-upload/server/content/files/16081235b28459---17349414620.pdfIn PDF document text
    • http://sgadsahodayatarntaran.org/sahodyatarntarannew/userfiles/file/pipevibawagibeli.pdfIn PDF document text
    • http://www.leesii.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a497ad6c0e8---56097970775.pdfIn PDF document text
    • http://daiichihr.com/uploads/news_file/17976439066.pdfIn PDF document text
    • https://www.pferde-fuer-unsere-kinder.de/wp-content/plugins/formcraft/file-upload/server/content/files/1607bd358a8280---30353476684.pdfIn PDF document text
    • https://www.msolartop.cz/wp-content/plugins/formcraft/file-upload/server/content/files/1609858f422992---fopogefebu.pdfIn PDF document text
    • https://www.lenoir-elec.com/wp-content/plugins/super-forms/uploads/php/files/5gssjjih3b0pbh5fgo4jdan0ca/1758443326.pdfIn PDF document text
    • https://www.formwork.co.uk/wp-content/plugins/super-forms/uploads/php/files/gmilmopv2cm9nn6840pt1eh6h4/94492614544.pdfIn PDF document text
    • https://kabelkyaobuv.sk/editor_uploads/files/zejulupomi.pdfIn PDF document text
    • http://galerie45.com/userfiles/file/susawatiziduvet.pdfIn PDF document text
    • http://www.k-24.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ba5c69dd34f---71300794611.pdfIn PDF document text
    • http://didopack.com/files/takajetogudefo.pdfIn PDF document text
    • http://ambulatorioveterinariosantanna.eu/userfiles/files/getepabilikawaz.pdfIn PDF document text
    • http://davidhammerstein.org/ckfinder/userfiles/files/93855730867.pdfIn PDF document text
    • http://alexandercdg.com/clients/36029/File/41127594897.pdfIn 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://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_off0000dd8e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDD8E 17384 bytes
SHA-256: 6759d78635ba066acb65caf0ab46c2c83eb6cc41360c38f1fbce346f8c3657b8
font_01_sfnt_off000109dc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x109DC 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000121f3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x121F3 10840 bytes
SHA-256: e626b9276366f034a4d9787d19d2da0a83dbc774bd7a3d547c69f5da11196138

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