Malicious PDF — malware analysis report

Static analysis result for SHA-256 528e60f5c99f47d1…

MALICIOUS

PDF

101.4 KB Created: 2021-07-17 21:25:57 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-14
MD5: b6382204f09c9afb8b749658e9d9bf76 SHA-1: 191fead912826d41e3347851cc861e6cf9aa495d SHA-256: 528e60f5c99f47d1aa76f3f961efa2bfa4862dca354db30142ab97a027b1a1b8
156 Risk Score

Malware Insights

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

The PDF contains numerous links pointing to other PDF files, many hosted on compromised CMS uploads. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for SEO poisoning or distributing further malware. The document body is heavily obfuscated and unreadable, providing no direct user-facing lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9959

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 http://dongkoo.com/uploads/editor/files/kimobo.pdf In PDF document text
    • http://banghetretruc.com/media/ftp/file/32343993988.pdfIn PDF document text
    • http://zavalinka.by/var/upload/file/numinuwojo.pdfIn PDF document text
    • https://sjalikave.hu/pictures/file/fajet.pdfIn PDF document text
    • https://majubesar.com/contents//files/42462772801.pdfIn PDF document text
    • https://himalmanpower.com/ckfinder/userfiles/files/rapubesotupepi.pdfIn PDF document text
    • https://www.dazzlingdecor.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16073e08cb8d75---jogitiletigugonasim.pdfIn PDF document text
    • http://geometramaurotozzi.it/userfiles/files/57150289946.pdfIn PDF document text
    • https://pankalconstructora.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609c4267cb292---41454644740.pdfIn PDF document text
    • http://wksystems.net/HotelEstimator/userfiles/file/rexevexaxefepezebukuses.pdfIn PDF document text
    • http://aberdeeneyes.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1608e4b37807e3---momakinuwat.pdfIn PDF document text
    • https://frennphotography.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ad4da95bdd8---buketira.pdfIn PDF document text
    • https://wscnaturalhealings.com/wp-content/plugins/super-forms/uploads/php/files/20a2adfbbc04a8dcff43a2f40c95e5df/39956441679.pdfIn PDF document text
    • https://archcosmeticstudio.com.au/wp-content/plugins/super-forms/uploads/php/files/0954bb98c1d11e0f679e331c6ddd9bc1/vadijox.pdfIn PDF document text
    • http://rustproofingottawa.com/userfiles/file/51600025365.pdfIn PDF document text
    • http://www.skupp.pl/wp-content/plugins/formcraft/file-upload/server/content/files/160c6d76825796---84810723215.pdfIn PDF document text
    • https://www.goldenplanet.dk/wp-content/plugins/formcraft/file-upload/server/content/files/160ab8bde20164---68992682411.pdfIn PDF document text
    • http://alphasigmaoverseas.com/userfiles/file/7782637579.pdfIn PDF document text
    • http://magogaralbamoble.com/galeria/files/3169631345.pdfIn PDF document text
    • http://ebslang.net/_UploadFile/Images/file/72690194869.pdfIn PDF document text
    • http://www.fotografoeventimilano.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607bbb650b321---gikefawixudakadin.pdfIn PDF document text
    • http://tetraeng.it/userfiles/files/pevufulegof.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/A3Ryygt5BCM/uplcv?utm_term=lord+of+the+rings+jack+o+lanternPDF 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_off00012891.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12891 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off000140a3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x140A3 17932 bytes
SHA-256: 5f9f3d7e357717cd751f3b5d89190d72ec62f5cf7cc4772e52e965d237dc9969
font_02_sfnt_off00016f59.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x16F59 10932 bytes
SHA-256: b94666c81efc48be60cf4ab86e6993b0914162ab1425a06880141bb4849ea8f0

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