Malicious PDF — malware analysis report

Static analysis result for SHA-256 3806dd6df40e079a…

MALICIOUS

PDF

86.6 KB Created: 2021-09-20 16:55:26 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 8c998cdadf9507842aae8e0e238b7523 SHA-1: 5810af1893c0e07d9738755f0090f9a1d57ea080 SHA-256: 3806dd6df40e079a7cf838e2aa658f760eea309849f296a9973a8dc022fd4c9e
196 Risk Score

Malware Insights

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

The PDF document was flagged by ML classifiers and ClamAV as malicious, with heuristics indicating it's a link farm and a lure for remote support tools. The document body, though heavily obfuscated, contains metadata suggesting it was generated by wkhtmltopdf, a tool often used to create PDFs from web content. The presence of multiple URLs pointing to PDF files on various domains, combined with the 'Remote-support tool lure' heuristic, strongly suggests a phishing or social engineering attack aimed at tricking users into installing remote access software.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9835

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • Remote-support tool lure high SE_REMOTE_SUPPORT_LURE
    Document instructs the user to install, open, or connect with a remote-support tool such as AnyDesk, TeamViewer, Quick Assist, or ScreenConnect — high-risk in an unsolicited document
  • 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://studioferrato.it/userfiles/files/45527069825.pdf In PDF document text
    • http://becucci.it/userfiles/files/54967292148.pdfIn PDF document text
    • https://inchirierielicopter.ro/wp-content/plugins/formcraft/file-upload/server/content/files/161385e37799a7---nakuvogikunowonuse.pdfIn PDF document text
    • http://aygroupmuh.com/image/files/numozufoferar.pdfIn PDF document text
    • http://unityproductions.com/upload/files/69649735209.pdfIn PDF document text
    • https://bepxuyenviet.com/upload/files/93203413472.pdfIn PDF document text
    • http://hstairan.com/fckeditor/editor/filemanager/connectors/php/userfiles/file/60369332093.pdfIn PDF document text
    • http://terwaarde.be/ckfinder/userfiles/files/66485105510.pdfIn PDF document text
    • https://tidaksusah.com/contents/files/1670997609.pdfIn PDF document text
    • http://n-production.com/upload/fckeditor/file/funofowizuwetom.pdfIn PDF document text
    • https://hmanagement.net/userfiles/file/93322371254.pdfIn PDF document text
    • http://www.melodypods.com/wp-content/plugins/formcraft/file-upload/server/content/files/161454e79b280f---gukubenudaf.pdfIn PDF document text
    • http://tbeaindia.com/userfiles/file/19573413473.pdfIn PDF document text
    • https://samajsutra.com/userfiles/files/xawekivokiridub.pdfIn PDF document text
    • http://rotang.net/userfiles/file/64177450657.pdfIn PDF document text
    • http://twilaw.com/files/files/70635945758.pdfIn PDF document text
    • http://tetrafluoro.com/upload/files/14898641352.pdfIn PDF document text
    • http://chemsdano.com/upload/files/dexavedezed.pdfIn PDF document text
    • https://xedulichhaiphong.vn/images/news/files/namonimij.pdfIn PDF document text
    • http://megatex-plast.ru/pub/file/wowaranesijo.pdfIn PDF document text
    • https://www.elektrobetrieb-scholz.de/wp-content/plugins/formcraft/file-upload/server/content/files/161426a94812e7---21831327180.pdfIn PDF document text
    • https://reha.bg/content/upload/file/30538447947.pdfIn PDF document text
    • https://nguoixunghekiev.vn/userfiles/file/wuxos.pdfIn PDF document text
    • http://igs.compcierge-asia.com/ckfinder/userfiles/files/13114617285.pdfIn PDF document text
    • https://proff-doors.ru/wp-content/plugins/super-forms/uploads/php/files/a008616d45e78ac805bf80f04dc88803/60454517628.pdfIn PDF document text
    • http://hnsunnyfood.com/d/files/jubatitofeledivisi.pdfIn PDF document text
    • http://ambulanceservice.pl/userfiles/file/29961963746.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/YTWXjIUwRh0/uplcv?utm_term=cara+remote+desktop+androidPDF 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_off0000f028.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF028 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0001083a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1083A 17340 bytes
SHA-256: 8e4a813148b121616d129024152f927e39e8a65c9f67c71251777eb181160f53
font_02_sfnt_off000134c2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x134C2 10628 bytes
SHA-256: e08c13a4af00ffb81d95e8fa2e19fb4f381011994ac8bc50196c1a7b5375304e

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