Malicious PDF — malware analysis report

Static analysis result for SHA-256 3fa8b803c85d951c…

MALICIOUS

PDF

74.2 KB Created: 2021-09-07 07:17:47 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: c52ba0ff258abc95d07cdf6c9d0f5db6 SHA-1: 1d35dbe0dc9e6270cf8201f56eba6c3c3a9b47e5 SHA-256: 3fa8b803c85d951c0b3b4a53adba6788b4fe8301f466375189e072a2067bd604
172 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample was detected as malicious by ClamAV and ML classifiers, indicating a high likelihood of malicious intent. It contains an embedded JavaScript stream and numerous external URIs, many of which are part of a link farm hosted on compromised or disposable domains. These links likely serve as redirects to phishing pages or malware download sites, consistent with a spearphishing attachment attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9990

Heuristics 8

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • Urgency / deadline lure low SE_URGENCY_LURE
    Document contains urgency or deadline language ('account will be terminated', 'action required within 24 hours', etc.) — useful context, but low-signal without other findings
  • 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://krisoc.ru/uplcv?utm_term=physical+science+grade+11+june+2016+memo+pdf PDF link annotation
    • https://celebicatering.com/upload/ckfinder/files/juwazanopazol.pdfIn PDF document text
    • http://albatrossmrn.com/konadnew/userfiles/file/zivijukerisen.pdfIn PDF document text
    • https://popcouncilinstitute.org/wp-content/plugins/super-forms/uploads/php/files/ebb12ac9bd80783e17ea071efef8a460/34592731101.pdfIn PDF document text
    • http://dolinakrzeptowa.pl/public/upload/ckfinder//userfiles/files/42544618788.pdfIn PDF document text
    • https://envida-nieuws.nl/bsb_website/upload_fck/file/34335308589.pdfIn PDF document text
    • http://fbrasil.com/userfiles/file///golenanabulapanomosivuwo.pdfIn PDF document text
    • http://studiocalderini.it/userfiles/files/82539490773.pdfIn PDF document text
    • http://tourister.kr/userfiles/file/vefepeloruguwaluv.pdfIn PDF document text
    • https://shotclock.ca/wp-content/plugins/super-forms/uploads/php/files/4beaabfe70974528c8294bae5071659d/98236122972.pdfIn PDF document text
    • http://greentreeprep.com/cote_dor_import/admin/ckfinder/userfiles/files/24483527876.pdfIn PDF document text
    • https://irantruck.ir/data/file/xejaxix.pdfIn PDF document text
    • http://bascobrunswick.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1611a4303c2a08---5608547989.pdfIn PDF document text
    • https://portofcrotone.com/dati/upload/file/19557449202.pdfIn PDF document text
    • http://fobosgrunt.ru/files/ckfinder/files/xusepomati.pdfIn PDF document text
    • http://www.kreasoft.mx/wp-content/plugins/formcraft/file-upload/server/content/files/16081ce1c4ccef---turalufuvazuwivupu.pdfIn PDF document text
    • https://www.shamshabaddiocese.org/files/js/ckfinder/userfiles/files/gukoxaw.pdfIn PDF document text
    • https://schreinerheusi.de/wp-content/plugins/formcraft/file-upload/server/content/files/160ac2e05cbcee---34723109700.pdfIn PDF document text
    • https://primeodontorj.com/wp-content/plugins/super-forms/uploads/php/files/318619f0378a3853a51e32e4463861e0/91049838466.pdfIn PDF document text
    • http://chocolatycakes.com/wp-content/plugins/formcraft/file-upload/server/content/files/160fc557c0428d---26176053564.pdfIn PDF document text
    • https://www.marjojaspers.nl/ckfinder/userfiles/files/76955244999.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_off0000bb4d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBB4D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000d35f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD35F 17108 bytes
SHA-256: e50903e269c37d95fe66ca70340ccdeb02a8e8a49da5a01a6faf511105de9178
font_02_sfnt_off0000ff42.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFF42 11776 bytes
SHA-256: 0acbaeb93d50c6757771aebf497b39943e1ed580c3785a1648bcbe39d798bf9e

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