Malicious PDF — malware analysis report

Static analysis result for SHA-256 81644335afd6a06b…

MALICIOUS

PDF

87.6 KB Created: 2021-07-25 18:46:22 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 56872f9284a4d746d51543b50ba97236 SHA-1: 25c16ef9a16725b240d008f513a9ec75cec7388c SHA-256: 81644335afd6a06bc7f6a808686a8a7bc603d08b8df2bb4c68000a034b713d4d
156 Risk Score

Malware Insights

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

The PDF contains a link farm pointing to multiple compromised WordPress sites, which in turn host other PDFs. This suggests a phishing or malware distribution campaign where the initial PDF serves as a lure to further malicious content. The ML classifier and ClamAV detection strongly indicate malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9949

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://unique.global/wp-content/plugins/super-forms/uploads/php/files/b94448513791abc3fe26e6c6f4d8e3f7/97542332206.pdf In PDF document text
    • https://adm.allianceflooring.net/wp-content/plugins/super-forms/uploads/php/files/08bb0103d611c2547c6e9b0a2a952d08/50445330726.pdfIn PDF document text
    • https://boyanbolyarski.com/userfiles/file/96773985124.pdfIn PDF document text
    • http://dmn.ca/wp-content/plugins/formcraft/file-upload/server/content/files/16077685483981---popus.pdfIn PDF document text
    • http://sicilyontable.it/userfiles/files/pexokalakivonulejaxefek.pdfIn PDF document text
    • http://www.mywil.ch/wp-content/plugins/formcraft/file-upload/server/content/files/1606f60b358bda---gipapiruzepupetudiko.pdfIn PDF document text
    • https://grandegroup.net/files/tifaxixujabadekezuk.pdfIn PDF document text
    • https://retentionstudentexperience.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a25bbd2e501---9837726541.pdfIn PDF document text
    • http://self119.net/upload/userfiles/2021/06/files/210602123230.pdfIn PDF document text
    • https://okinawa4d.com/contents//files/dotevi.pdfIn PDF document text
    • http://aivieksteslaivas.lv/userfiles/file/tufaduj.pdfIn PDF document text
    • http://bigband-ulm.de/userfiles/files/94294001331.pdfIn PDF document text
    • http://www.petersmetalstitching.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/160846cba70309---58771782222.pdfIn PDF document text
    • https://www.hdcorp.com.br/wp-content/plugins/super-forms/uploads/php/files/beheiifqel86q8g8d7ari5bpq4/kafejilazol.pdfIn PDF document text
    • https://plumcourse.com/wp-content/plugins/super-forms/uploads/php/files/aa3697c4640eea85060667d5475f7329/93157479911.pdfIn PDF document text
    • https://genesisbehaviorcenter.com/wp-content/plugins/super-forms/uploads/php/files/94bc45c1b500b4c9ed95936282688ff4/donukavotifuwir.pdfIn PDF document text
    • http://southportrubbish.com/wp-content/plugins/formcraft/file-upload/server/content/files/16075610222071---wibaxujegezusodavidabe.pdfIn PDF document text
    • http://witnesstherealist.com/wp-content/plugins/super-forms/uploads/php/files/83076b5498cfe871bbd5dca9c4b584a8/79019337610.pdfIn PDF document text
    • http://kaithompson.com/userfiles/file/50314953466.pdfIn PDF document text
    • https://nhaban24h.com.vn/wp-content/plugins/super-forms/uploads/php/files/g319vk65oe8p7u7ih1o28re8gl/67000042603.pdfIn PDF document text
    • http://www.commandinglife.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606ea9070f213---jowokur.pdfIn PDF document text
    • http://ultraljud.nu/bild/files/vikonapisedifugoxef.pdfIn PDF document text
    • http://www.sunargrup.com.tr/wp-content/plugins/super-forms/uploads/php/files/jcual05k5h6ik4dj2qmk8qrj41/80145789525.pdfIn PDF document text
    • http://studiogaleazzo.eu/userfiles/files/74778404603.pdfIn PDF document text
    • http://dongkoo.com/uploads/editor/files/93751121535.pdfIn PDF document text
    • http://gabinetortodontyczny.eu/userfiles/file/fogumuwuni.pdfIn PDF document text
    • http://www.molinoag.com/wp-content/plugins/formcraft/file-upload/server/content/files/16076a4ada9b13---siwomularikadewamimu.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/YTWXjIUwRh0/uplcv?utm_term=how+much+to+buy+a+black+pantherPDF 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_off0000f2e5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF2E5 16968 bytes
SHA-256: 5b4d7a826f7a094959b9b55eaa52ed8ae9b69562a21805a3b57b1b0170a02e5f
font_01_sfnt_off00011f33.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11F33 10900 bytes
SHA-256: db27f7d49773d286ce907fdf31fa8b992d7000948fb21168d4841d063e12f1b8
font_02_sfnt_off00013813.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13813 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1