Malicious PDF — malware analysis report

Static analysis result for SHA-256 b3e1d72d90d2c58d…

MALICIOUS

PDF

78.5 KB Created: 2021-09-11 10:44:07 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 6d3ed26aa47a6a4c5984a2f4161d38dc SHA-1: bf5221e1d6fb6e795c66b1bf264f08161e6049b9 SHA-256: b3e1d72d90d2c58de3a88d15c21d0ef5edf27c541da7828a6c74fc9437322dff
156 Risk Score

Malware Insights

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

This PDF file was detected as malicious by ClamAV and an ML classifier. It functions as a link farm, containing numerous embedded URLs that point to potentially compromised websites. The heuristic 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' specifically indicates that these links are hosted on compromised WordPress upload directories, suggesting an attempt to distribute malicious content or phish users. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, providing no direct user-facing content but serving as a vessel for the malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9968

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://kachhiproperties.com/wp-content/plugins/super-forms/uploads/php/files/b508250c2408f5426970d8e702038c0e/21186235043.pdf
    • https://btegypt.com/file/73020259379.pdf
    • http://robalton.es/Albums/images/file///bavinupudenat.pdf
    • http://lilit-realty.com/wp-content/plugins/super-forms/uploads/php/files/htgqhmh86hs3b22fsi7okfb4o0/mozuzavuvoxesigitugodas.pdf
    • https://coonvalleycc.com/userfiles/file/soxivajamakiwozu.pdf
    • https://fultoys.com/userfiles/65993488479.pdf
    • http://cz-synergy.cz/data/file/84891036400.pdf
    • http://moriefrusca.com/userfiles/files/jafitoxowadiboruzib.pdf
    • https://pensiuneaselina.ro/userfiles/file/35315987990.pdf
    • http://fittbikese.hu/files/file/67487094656.pdf
    • http://hmondo.com/userData/board/file/45431593104.pdf
    • http://orderkiwicafe.com/uploads/files/tutusogidejusesojog.pdf
    • http://namngonviet.vn/user-/files/84337213100.pdf
    • https://cytairtool.com/test/userfiles/file/20210906_0c189.pdf
    • https://www.taxiserviceh24.com/wp-content/plugins/formcraft/file-upload/server/content/files/161350786e7e6d---81343786254.pdf
    • http://chayka-svg.ru/files/lolaw.pdf
    • https://frigosztufi.ro/ckfinder/userfiles/files/99796394921.pdf
    • http://taxilitomerice.cz/ckfinder/userfiles/files/ranopobefonazoxivamiv.pdf
    • http://imobilestore.de/userfiles/file/wumemidupo.pdf
    • http://vizugy.hu/uploads/files/files/34497380705.pdf
    • https://recrut.com/files/files/93984419648.pdf
    • http://hwangtosidae.com/userData/ebizro_board/file/69047519546.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/3CAf4wW3hvY/uplcv?utm_term=human+resource+management+gary+dessler+15th+edition+pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000cb32.bin
0dbb0ab5d4ecef2902842a0734b40a2d3ea7c4dcf362d7786675df70801a6582
pdf-font-stream PDF embedded font (sfnt) at offset 0xCB32 11456 bytes
font_01_sfnt_off0000e5ec.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xE5EC 16792 bytes
font_02_sfnt_off0000fdfe.bin
d40351ca5e33830dc0193486678d40405006e8726f179ad57dc45e7267070d42
pdf-font-stream PDF embedded font (sfnt) at offset 0xFDFE 17976 bytes