Malicious PDF — malware analysis report

Static analysis result for SHA-256 b4da00b4fef160a5…

MALICIOUS

PDF

84.2 KB Created: 2021-09-13 14:53:15 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: c087c65dbbb2bac660f7c0b81d27069c SHA-1: 1f0f9cf59bf86d297c1b0b15ebd40b9b018eee38 SHA-256: b4da00b4fef160a5aca83b79a62ef1438822158cbc01d4836d20dd69b80399a8
156 Risk Score

Malware Insights

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

The PDF was flagged by ML classifiers and ClamAV as malicious. Heuristics indicate it functions as a link farm, with numerous embedded URLs pointing to compromised or disposable hosting. The presence of multiple links on potentially compromised CMS upload directories suggests an attempt to distribute malicious content or phish users. No scripts were extracted from this sample.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9912

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://dom4m.by/userfiles/files/mizobutoxetumibusomos.pdf In PDF document text
    • http://lookupagency.es/wp-content/plugins/formcraft/file-upload/server/content/files/1613a06360e285---93735323033.pdfIn PDF document text
    • https://netwindowvn.com/uploads/userfiles/file/gupuvafozurimotebuko.pdfIn PDF document text
    • https://nationalcardsolutions.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613970689c409---baguvijobubamobupak.pdfIn PDF document text
    • http://wijnhuis-vaessen.nl/site/data/ws/files/32444703080.pdfIn PDF document text
    • https://nikunjfoundation.org/ckfinder/userfiles/files/vabozezeduxudusigopuwa.pdfIn PDF document text
    • http://dotykbylinky.sk/_subory/subory/40414367739.pdfIn PDF document text
    • https://sevenhillsgroup.net/ckfinder/userfiles/files/61310816198.pdfIn PDF document text
    • http://topenglish.sk/app/webroot/gallery/files/36413241434.pdfIn PDF document text
    • https://holocaustresearch.pl/nowy/photo/file/98999449397.pdfIn PDF document text
    • https://ciiinnovationsummit.com/ci/userfiles/files/14431864493.pdfIn PDF document text
    • https://editionsitaliques.com/userfiles/file/52720264609.pdfIn PDF document text
    • https://arnetbilgisayar.com/upload/ckfinder/files/1383181712.pdfIn PDF document text
    • http://baobianhkhang.com/upload/files/85579378247.pdfIn PDF document text
    • https://sinarlangit1.com/contents/files/58119447795.pdfIn PDF document text
    • http://www.reroofingbrisbaneqld.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1613090f3bbd6a---gemipetapitipikopomaleni.pdfIn PDF document text
    • http://kiajihlava.cz/UserFiles/File/jevut.pdfIn PDF document text
    • http://tkhomedeco.com/assets/uploads/ckedit/files/20210912180244.pdfIn PDF document text
    • https://archielectronics.com/userfiles/files/8369161243.pdfIn PDF document text
    • http://verkoop-je-wagen.be/wp-content/plugins/formcraft/file-upload/server/content/files/1613f06c60f951---96955321749.pdfIn PDF document text
    • https://hoatuoi360.vn/uploads/files/sokamitin.pdfIn PDF document text
    • http://www.christinemartin.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16132714fad946---rasaxili.pdfIn PDF document text
    • http://tao-oita.com/admin/upload_filesfile/korajofukopuxigen.pdfIn PDF document text
    • https://chsins.tw/uploads/files/202109120432195157.pdfIn PDF document text
    • http://iqlacpro.vn/emotive/upload/files/73723123441.pdfIn PDF document text
    • http://mydreamtuscanwedding.com/editor_up/94055487863.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/Om9ozkHLxGw/uplcv?utm_term=answering+spam+emailsPDF 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_off0000e29e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE29E 10444 bytes
SHA-256: 3d154a311856939071942be84bb6e7503674e7e5207e1a6b543b19019d6d7e74
font_01_sfnt_off0000fa53.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFA53 18576 bytes
SHA-256: 136d5e7d6278b4e73e23c6060b612be7c1fc1deeb0c1df48842b8ae4a3a6c873
font_02_sfnt_off00012ad8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12AD8 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1