Malicious PDF — malware analysis report

Static analysis result for SHA-256 f66280540cd409cb…

MALICIOUS

PDF

89.5 KB Created: 2021-08-21 08:10:51 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: 958ed19fcaabc0cc0db4b045feed919e SHA-1: e38eb9932cb2d6828d66150fc7c5a48b56b9a8c2 SHA-256: f66280540cd409cb10a60ea765708cbfb10aaa8971ad12e2b3e6253b400d8c57
196 Risk Score

Malware Insights

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

The sample is a PDF document that exhibits characteristics of a social engineering attack, specifically a 'ClickFix' variant. It contains numerous links to external websites, many of which appear to be hosted on compromised CMS platforms or disposable domains, suggesting a link farm or phishing lure. The 'SE_CLICKFIX' heuristic indicates the document likely instructs the user to press Win+R or paste a command into a terminal, a common technique to bypass macro restrictions and execute arbitrary code. While no scripts were directly extracted, the overall pattern suggests the PDF is designed to lead the user to execute a malicious command, likely downloading and running a second-stage payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9933

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
  • ClickFix social engineering attack high SE_CLICKFIX
    Document instructs the user to press Win+R or paste a command into a terminal — consistent with ClickFix attacks that bypass macro restrictions by tricking users into running malicious commands directly
  • 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 http://dolphinkorea.com/files/files/45869038931.pdf In PDF document text
    • http://pnktools-th.org/ckfinder/userfiles/files/mopebavede.pdfIn PDF document text
    • https://www.pietri-automobiles.com/wp-content/plugins/super-forms/uploads/php/files/5uq5e25bnqe0koi00vimkdnpj4/49929221101.pdfIn PDF document text
    • https://www.capitalroofingct.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609847293dd95---12853607917.pdfIn PDF document text
    • http://iberryhomemade.com/userfiles/files/10163895396.pdfIn PDF document text
    • https://tdfstore.it/file/16690657234.pdfIn PDF document text
    • http://www.optimizecost.com/admin/ficheros_fckedit_subidos/25175955943.pdfIn PDF document text
    • http://www.alwaysflorida.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a99fcb37e17---zeponoruxuwopiwadazoboxa.pdfIn PDF document text
    • http://jagodkaprzedszkole.pl/userfiles/file/nuzilajufosawi.pdfIn PDF document text
    • http://www.sensible-seeds-premium.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607051961f32e---18029316788.pdfIn PDF document text
    • https://www.pharmaright.ca/wp-content/plugins/super-forms/uploads/php/files/l2a72s1b4t3584hd5sk84ku555/tutijodositalalinin.pdfIn PDF document text
    • https://thekolkatapackersmovers.com/ckfinder/userfiles/files/39360531882.pdfIn PDF document text
    • http://stepsforstarlight.com/clients/c/c6/c668404594a1c08d975ab50c7bec58f6/File/vobivomelo.pdfIn PDF document text
    • https://www.elshandmadedesign.nl/ckfinder/userfiles/files/45598152843.pdfIn PDF document text
    • https://www.stamfordtaxis.com/wp-content/plugins/super-forms/uploads/php/files/1a5un19c20o1vlhnnscvp54i8u/ninovapejixojuxodume.pdfIn PDF document text
    • http://www.theagentpipeline.com/wp-content/plugins/formcraft/file-upload/server/content/files/16099c68f46451---xozijisanoweton.pdfIn PDF document text
    • http://stadion-zarya.ru/ckfinder/userfiles/files/73056926296.pdfIn PDF document text
    • http://brenno-tojestto.pl/userfiles/file/5878319531.pdfIn PDF document text
    • https://www.frontierexim.com/wp-content/plugins/super-forms/uploads/php/files/4bj895ns3356n1kbbdv0eqqhtf/81992270176.pdfIn PDF document text
    • https://beribuket.ru/wp-content/plugins/super-forms/uploads/php/files/6b00a37bc2c1f9c81a0040c5c18deba0/61784973952.pdfIn PDF document text
    • https://bowenpainter.com/wp-content/plugins/formcraft/file-upload/server/content/files/160747785bdc4e---3349184215.pdfIn PDF document text
    • http://admio.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1612030455d5ce---zadulazeketutanakaguwab.pdfIn PDF document text
    • http://fantasypartyentertainment.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609923e611add---mekulabawuvanogarotu.pdfIn PDF document text
    • http://momsystem.ru/public/file/96691574550.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/BvfzZFkJO3s/uplcv?utm_term=how+to+install+minecraft+inventory+pets+modPDF 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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e229.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE229 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000fa3b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFA3B 16768 bytes
SHA-256: 8be7ae71a3b411f756b28bf20b3b333d57be55d1131264e54b23bea9abf2908b
font_02_sfnt_off000125f6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x125F6 16064 bytes
SHA-256: a013ce2342554bbd70a9f85285a6053b67e9b25eaba0dd22223cc179b1b1ea16
font_03_sfnt_off00013b0b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13B0B 11040 bytes
SHA-256: e3e31f3f066ef4d487805c2335236eb5eadc41c071518ffcf40bbcdcf7da5444

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