Malicious PDF — malware analysis report

Static analysis result for SHA-256 5afd3d63f12baa6e…

MALICIOUS

PDF

72.8 KB Created: 2021-04-13 18:33:50 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-29
MD5: de5245fe39d17623e9420e3e5b3f0b1a SHA-1: dde7bc0335097aaa517c459f50c5c3b796dcbf0b SHA-256: 5afd3d63f12baa6e8381866be6ae3ba40e7f88fc1deb0923e6fde2eeeb18f615
126 Risk Score

Malware Insights

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

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs pointing to link farms hosted on various domains, suggesting an attempt to direct users to potentially malicious content. The document body is heavily obfuscated and unreadable, but the presence of 'wkhtmltopdf' in the metadata indicates it was likely generated programmatically.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://www.osgeurope.com/sites/osg-corporate.dev/files/webform/nutuzisujobipusife.pdf In PDF document text
    • http://www.friendlycc.com/sites/default/files/webform/zuguxinukebezukul.pdfIn PDF document text
    • https://www.osgeurope.com/sites/osg-corporate.dev/files/webform/3563422068.pdfIn PDF document text
    • http://klm3fg.grhosting.cz/sites/default/files/webform/files/40110328039.pdfIn PDF document text
    • https://www.jwico.com/sites/default/files/webform/pagijan.pdfIn PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/93477879009.pdfIn PDF document text
    • https://extranet.blanchisserie-toulousaine-de-sante.com/sites/extranet.blanchisserie-toulousaine-de-sante.com/files/documents/justificatifs/29410319198.pdfIn PDF document text
    • http://oaklandchildcare.org/sites/default/files/webform/ligexupasofobepis.pdfIn PDF document text
    • https://www.jsif.org/sites/default/files/webform/54250685962.pdfIn PDF document text
    • https://www.jsif.org/sites/default/files/webform/54003515034.pdfIn PDF document text
    • http://www.muttypawsacademy.com/sites/default/files/webform/vaccines/17184396690.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/PmAiG5ZyT-k/uplcv?utm_term=csgo+knife+pngPDF link annotation
    • https://lib.asu.edu/system/files/webform/85824103047.pdfIn PDF document text
    • https://drones.princeton.edu/system/files/webform/61493424170.pdfIn PDF document text
    • https://community.princeton.edu/system/files/webform/13590028771.pdfIn PDF document text
    • https://www.ice.cam.ac.uk/sites/www.ice.cam.ac.uk/files/webform/10713621665.pdfIn PDF document text
    • https://printandmail.princeton.edu/system/files/webform/42849177422.pdfIn PDF document text
    • https://campusrec.princeton.edu/system/files/webform/4552140304.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://scripts.sil.org/OFLIn PDF document text
    • https://savannah.gnu.org/projects/freefont/In PDF document text
    • http://www.gnu.org/licenses/In PDF document text
    • http://www.gnu.org/copyleft/gpl.htmlIn PDF document text

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000c435.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC435 3928 bytes
SHA-256: f8c88f32a3f549a4c06971ba64ac7c5f8ca099a986aefa77c8582870e284fc28
font_01_sfnt_off0000d224.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD224 4700 bytes
SHA-256: 3f498fdc4ba4ee7b988b6f1c706c0c182894af9a20840a95ae5364f1c6003b16
font_02_sfnt_off0000e249.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE249 10368 bytes
SHA-256: d8b8b5cc240d99c7ca56aef817b4ed954e25fee75efcc9244609e00a8ab095b0
font_03_sfnt_off000105bb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x105BB 6068 bytes
SHA-256: 4b45f33c909d1de4119f908b2e4eeec8b51571bcf8b126b8fe9c8b95bec6d9c2