Malicious PDF — malware analysis report

Static analysis result for SHA-256 e61b3461537865d7…

MALICIOUS

PDF

79.8 KB Created: 2021-09-11 05:30:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: b6e646e5e06196650914a0b2e32c56c9 SHA-1: e20e9b1dc1067f913ca14ecf55356899d0fed115 SHA-256: e61b3461537865d79aedcc91cdb7b8e9505ceca0d0c4479bc285ed5de4788cfd
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by multiple heuristics as malicious, including a ML classifier and ClamAV, indicating a high likelihood of malicious intent. The presence of numerous external URIs, many pointing to compromised CMS upload storage or disposable hosting, suggests a phishing or malware distribution campaign. The document body, though heavily obfuscated, contains metadata indicating it was generated by wkhtmltopdf, a tool often used to create malicious PDFs.

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://crysiq.ru/uplcv?utm_term=head+first+c%23+2019+pdf PDF link annotation
    • https://ccskin.com/geektic/files/woludibanilujuze.pdfIn PDF document text
    • https://pavaniautismschools.com/wp-content/plugins/super-forms/uploads/php/files/rbr68m374v9ktdd9ar9rjja12f/55132045298.pdfIn PDF document text
    • https://workinhotel.com/upload/fckfile/37958218806.pdfIn PDF document text
    • https://nikosdimos.gr/userfiles/file/35415456683.pdfIn PDF document text
    • https://himalayanespresso.com/espresso_ckfinder/userfiles/files/86079404921.pdfIn PDF document text
    • http://rebizplus.com/userfiles/file/bitulumibesonunilerev.pdfIn PDF document text
    • http://naphotelbangkok.com/userfiles/files/19094907445.pdfIn PDF document text
    • http://opgzvh.hr/upload/file/71073036375.pdfIn PDF document text
    • http://gzcil.com/uploadfile/files/47946811109.pdfIn PDF document text
    • http://www.neoneofitou.com/ckfinder/userfiles/files/70965736390.pdfIn PDF document text
    • http://boekenwinkelindex.nl/images/uploads/lilidejuwuwutixajirebalo.pdfIn PDF document text
    • https://cargobull.cz/res/file/53211430520.pdfIn PDF document text
    • http://www.bewegeninarnhem.nl/wp-content/plugins/formcraft/file-upload/server/content/files/161303762c0136---robakojipu.pdfIn PDF document text
    • http://safarekhoob.ir/basefile/safarekhoobir/files/kebonub.pdfIn PDF document text
    • https://szallas-karpatalja.hu/upload/wawetof.pdfIn PDF document text
    • http://eng.sut.ac.th/tce/2016/administrator/ckfinder/userfiles/files/77001823441.pdfIn PDF document text
    • http://4bx.pl/public/file/28229329359.pdfIn PDF document text
    • https://totalmediasolutions.ae/ckfinder/userfiles/files/16704861269.pdfIn PDF document text
    • http://efuturesthai.com/uploads/file/57957929724.pdfIn PDF document text
    • https://trompis-tondschungel.de/userfiles/file/dedereb.pdfIn PDF document text
    • https://happen.webasl.com/userfiles/file/12901725726.pdfIn PDF document text
    • http://bradhelferlaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/69181870725.pdfIn PDF document text
    • http://globalbizkorea.com/userData/board/file/52577847689.pdfIn PDF document text
    • http://triumphtoday.org/wp-content/plugins/formcraft/file-upload/server/content/files/1613729fa915de---zodagugitasirozojenizag.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_off0000d6b6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD6B6 10192 bytes
SHA-256: 93e92e36f243b713fea43bac4d60bf1c7b76392b7609bd9c491df15cfd23218b
font_01_sfnt_off0000ed9b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xED9B 17124 bytes
SHA-256: 49aaff625cc5c0694359b6416d4845d743961bc4f10d201c04466678b47b8e52
font_02_sfnt_off000119e1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x119E1 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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