Malicious PDF — malware analysis report

Static analysis result for SHA-256 21fbb769b0653a2a…

MALICIOUS

PDF

100.5 KB Created: 2021-09-05 01:57:13 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 3a6103f172e873e32cca53c83859548e SHA-1: c8aa8cfbe9981f0213b85901a7b07000a8df9a4c SHA-256: 21fbb769b0653a2acbd7d2f4f179ffce27189f1e1757803255cf478359c76c15
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs that form a link farm, directing users to various websites. Heuristics indicate these links are intended for SEO manipulation and point to compromised CMS uploads, suggesting a phishing or malware distribution scheme. The ML classifier and ClamAV detection strongly indicate malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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://pistant.ru/uplcv?utm_term=niosh+pocket+guide+to+chemical+hazards+2010+pdf PDF link annotation
    • http://levne-pohary.cz/UserFiles/File/30846373688.pdfIn PDF document text
    • https://srinivasagroup.com/ci/userfiles/files/sekakebodetuzemim.pdfIn PDF document text
    • http://livelyway.com/ckfinder/userfiles/files/93222529764.pdfIn PDF document text
    • http://e-sportis.com/images/upload/76160720453.pdfIn PDF document text
    • https://tolgyesvolgy.hu/userfiles/file/24454167721.pdfIn PDF document text
    • https://adbadog.com/wp-content/plugins/super-forms/uploads/php/files/5043cb0256117aca4f16e63f2b0fa3ee/3343402049.pdfIn PDF document text
    • http://npi-management.org/ressource/site-image/files/memodov.pdfIn PDF document text
    • https://eliteplacementagency.com/uploads/files/93712070402.pdfIn PDF document text
    • http://localhomesales.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/16100d6e1bedb2---fuvedagonegomozafideful.pdfIn PDF document text
    • https://nhaban24h.com.vn/wp-content/plugins/super-forms/uploads/php/files/jfbfimkrrbsg2ng5v5sg4i0hm9/63086197095.pdfIn PDF document text
    • http://www.siscard.com/wp-content/plugins/formcraft/file-upload/server/content/files/16084a3853cbee---30039067174.pdfIn PDF document text
    • http://www.specemc.ru/upload/files/18145638438.pdfIn PDF document text
    • https://daynexweb.com/upload/ckfinder/files/zenuruvumumoridonevakixof.pdfIn PDF document text
    • http://viquadro.com/userfiles/files/80704629407.pdfIn PDF document text
    • http://mlead.net/images/e/file/kuzejige.pdfIn PDF document text
    • http://novussiteyonetimi.com/uploads/file/44842578913.pdfIn PDF document text
    • http://tutek.eu/userfiles/file/bikerikuxelinosi.pdfIn PDF document text
    • http://www.restorationservice.ca/wp-content/plugins/formcraft/file-upload/server/content/files/1607ec755a5ba1---xifepakegogedomufapuvak.pdfIn PDF document text
    • https://doanandieuduong295doson.vn/namthuan/images/news/files/92416507122.pdfIn PDF document text
    • https://educhina.mn/editor/files/namanutebav.pdfIn PDF document text
    • http://aldara-latinoamerica.com/userfiles/file/87224621475.pdfIn PDF document text
    • https://koltoztetes-szallitas-lomtalanitas.excore.hu/ckfinder/userfiles/files/xagifawitiridokezelip.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_off00011a5d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11A5D 20572 bytes
SHA-256: 9f7ff228e9b8fd9a41031bbeac60e16fccaf62ceb2738927fdcd4ab48a61e07e
font_01_sfnt_off000150bb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x150BB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000168d2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x168D2 11488 bytes
SHA-256: 52054e532540a2d00afed0be43fdf604f19a5a1ed60d98bfad7f483ce32fee73