Malicious PDF — malware analysis report

Static analysis result for SHA-256 caf37c65c05066a5…

MALICIOUS

PDF

75.0 KB Created: 2021-04-19 17:54:04 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-29
MD5: b9f5b088edd08ff84545019687bb991e SHA-1: 123914f7b7761865ae0e46a3629dfd6ded5ac9b4 SHA-256: caf37c65c05066a5f4433864c5556e0e05cb376531a7fcc111f27814d16b36a5
126 Risk Score

Malware Insights

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

The PDF file was flagged as malicious by both ML classifiers and ClamAV, indicating a high likelihood of malicious intent. The document's content, though appearing to be about woodworking, contains embedded URLs that are part of a link farm, a common tactic for phishing or malware distribution. The presence of multiple external URIs and the ML detection strongly suggest this PDF is designed to exploit vulnerabilities or trick users into downloading further malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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.afscme65.org/system/files/webform/baxuwobokorexifiri.pdf In PDF document text
    • https://ambrose.edu/sites/default/files/webform/mamak.pdfIn PDF document text
    • http://klm3fg.grhosting.cz/sites/default/files/webform/files/16831560309.pdfIn PDF document text
    • http://klm3fg.grhosting.cz/sites/default/files/webform/files/40110328039.pdfIn PDF document text
    • http://klm3fg.grhosting.cz/sites/default/files/webform/files/vewamilobofesiwukor.pdfIn PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/59286961246.pdfIn PDF document text
    • https://www.jwico.com/sites/default/files/webform/23528315583.pdfIn PDF document text
    • http://oaklandchildcare.org/sites/default/files/webform/ponezilineg.pdfIn PDF document text
    • http://www.pbttphtk.gov.my/sites/default/files/webform/238550972.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/58588935603.pdfIn PDF document text
    • http://www.friendlycc.com/sites/default/files/webform/zuguxinukebezukul.pdfIn PDF document text
    • https://www.jts.org.jo/sites/default/files/webform/96043924660.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://www.daltonmaag.com/In PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/YTWXjIUwRh0/uplcv?utm_term=woodworking+pdf+free+downloadPDF link annotation
    • https://www.vub.be/sites/vub/files/webform/pagilavamuvawasaxega.pdfIn PDF document text
    • https://drones.princeton.edu/system/files/webform/66931006591.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

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000dbeb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDBEB 4908 bytes
SHA-256: 054548dac42a7794e0ce0c12275617a9fbe9bab8f336f1092c2ec0ec270a60b8
font_01_sfnt_off0000ecc4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xECC4 10708 bytes
SHA-256: 585c29fc3b1ed1b6f65636700285ab5a6835dcc04b96a5804c1bc988457c1a41
font_02_sfnt_off00011118.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11118 4324 bytes
SHA-256: a542ec26cea93e049a2e27cd59b1347dd9bbdea13775fd7b822b3c2b3136116f

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