Malicious PDF — malware analysis report

Static analysis result for SHA-256 c87522c35583c63c…

MALICIOUS

PDF

82.3 KB Created: 2021-09-05 07:53:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 8bd363604cd81b44d4f5a0c0a71fe9d6 SHA-1: 5bce3c111678713abcd3d33ca397e48069d595c5 SHA-256: c87522c35583c63cf057c4acadc0e00766357a8bcd86fb89c6f001b51ae29a66
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains a large number of links pointing to other PDF files, many of which are hosted on compromised CMS upload directories. This behavior is indicative of a link farm, often used for SEO manipulation or to distribute malicious payloads. The ML classifier and ClamAV detection strongly suggest malicious intent, likely related to phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9972

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://library.nesdb.go.th/ic/admin/ckfinder/userfiles/files/zigowumimujaki.pdf In PDF document text
    • http://avision-italia.com/userfiles/files/25450045975.pdfIn PDF document text
    • https://alignerco.com/wp-content/plugins/super-forms/uploads/php/files/0ba9356ecc4ae2dce2a2d141f82ed6ce/58301727665.pdfIn PDF document text
    • https://jnfarley.com/wp-content/plugins/super-forms/uploads/php/files/1658fvdck3fq37n15an7pvino6/dolowibawunonuzebedaguso.pdfIn PDF document text
    • http://ifaistos.reality.gr/~triantaf/images/file/jibanoxudemufapoxegika.pdfIn PDF document text
    • https://manenshop.com/upload/files/nimirovoretefoxoda.pdfIn PDF document text
    • https://www.grandiosa.is/wp-content/plugins/super-forms/uploads/php/files/dep7srleis6qth6hkbei7d7i90/24814473633.pdfIn PDF document text
    • http://hasyo.net/files/file/54824910967.pdfIn PDF document text
    • https://www.baptistenhardenberg.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160a7f18a5d525---bawadokurutoremewululan.pdfIn PDF document text
    • https://www.grecosalesinternational.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612a25ad18424---97988441395.pdfIn PDF document text
    • https://unibel.pl/pliki/upload/file/gaginomufi.pdfIn PDF document text
    • https://www.hdontheroadnapoli.it/wp-content/plugins/formcraft/file-upload/server/content/files/160b9b26667de4---fidemememapukepisidotoba.pdfIn PDF document text
    • https://vickers-electronics.co.uk/wp-content/plugins/super-forms/uploads/php/files/7dbd12f203f871d28bc044a701400eb6/5218073861.pdfIn PDF document text
    • http://hillsclinic.com/fckeditor/editor/filemanager/connectors/php/userfiles/file/18464224361.pdfIn PDF document text
    • http://hart-metale.pl/gimnazjum/userfiles/file/nudimo.pdfIn PDF document text
    • http://asea-admin.com/_userfiles/file/20210516193629.pdfIn PDF document text
    • http://www.elsecretodelolivo.com/wp-content/plugins/formcraft/file-upload/server/content/files/161066e362457a---84884651873.pdfIn PDF document text
    • http://ajtoablakcentrum.com/_user/file/fojovomuwo.pdfIn PDF document text
    • http://bjallstar.com/upload/file/goluvikusisusi.pdfIn PDF document text
    • http://amtusa.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607ca0d1c32e6---xesoverexevemoxibidu.pdfIn PDF document text
    • http://sinice-rasy.cz/files/file/24961309299.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/FevRqgeaUVY/uplcv?utm_term=list+of+nursing+colleges+in+kerala+with+contact+details+pdfPDF 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_off0000d887.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD887 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f09e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF09E 11132 bytes
SHA-256: e8158255e30a4d22cafc85de6edd025cb41784165a7e435ce6c81eadd6c8007f
font_02_sfnt_off00010a70.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10A70 18904 bytes
SHA-256: 75b3fba4e31521e90bfd24ce86a66b6debf707804506920d2df7356df29be623

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