Malicious PDF — malware analysis report

Static analysis result for SHA-256 81f16365bf042352…

MALICIOUS

PDF

74.4 KB Created: 2021-05-19 00:24:56 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-08-20
MD5: 9f4a1402df6c67199915467b73cb02ce SHA-1: c2a3ad3a51abd6950106ab506ec5ab1e649e8d3e SHA-256: 81f16365bf04235291ad09ebfa2718a74c83cc5987c9c2b30db37a69bc7e421a
184 Risk Score
Tags
free-cdn-ebook-manual-lure

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The PDF contains embedded links that point to known malicious redirector infrastructure, as indicated by the PDF_MALICIOUS_REDIRECTOR_LINK heuristic. The document body, though heavily obfuscated, suggests a lure related to appliance repair, which is a common tactic for phishing or malware distribution. The ML classifier and ClamAV detection further support the malicious nature of this file.

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
  • PDF links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK
    PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
  • 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.
  • 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://crophysi.ru/strik?utm_term=how+to+reset+ice+maker+on+kenmore+elite+refrigerator In PDF document text
    • http://pafiwuz.66ghz.com/geranizokid.pdfIn PDF document text
    • http://vuvopogawuxaxax.22web.org/ceibal_plataforma_crea_2.pdfIn PDF document text
    • http://kefisel.22web.org/rifewapifovozodew.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4490949/normal_6030e9a2295f6.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4423428/normal_6007a67fa3a89.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4485010/normal_6019cedcd9390.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://refofigeto.epizy.com/sukefukijipe.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/19f66f6b-d7ca-4feb-b008-fe25d0199a6f/futugivunakovop.pdfIn PDF document text
    • http://fikirifulok.epizy.com/takisovefiseni.pdfIn PDF document text
    • http://zofawuzimiva.rf.gd/wawimozabikugepalino.pdfIn PDF document text
    • http://zinezalidoratov.rf.gd/21811953217.pdfIn PDF document text
    • https://s3.amazonaws.com/meludav/informal_report_format_in_technical_writing.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/51f45eb3-efdb-40e2-8bfa-41c31d01246c/32837747464.pdfIn PDF document text
    • https://s3.amazonaws.com/viwoxuz/pumobad.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/deeb3386-3ad2-4cae-9f5a-1bb4911bf5b0/63055946379.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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e67e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE67E 5320 bytes
SHA-256: a02f2af8e43188fb64307c719963b9447683db17b8ea8b25aafa7aaa341e440a
font_01_sfnt_off0000f892.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF892 10412 bytes
SHA-256: 4ac8bd87b21b92693712d026b586cdffd70cff10389f8bc0d635f84cffb37da1

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