Malicious PDF — malware analysis report

Static analysis result for SHA-256 8157c61ad81b64bb…

MALICIOUS

PDF

73.0 KB Created: 2021-02-25 21:51:40 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-22
MD5: 567ccc952676daa180658d505dd604d6 SHA-1: 6a0fe8eb173e7c23ffd54236376ef64ab969192d SHA-256: 8157c61ad81b64bbf1ed36791f77f0551107af7c19f6ad2bba00aa9bf425caae
184 Risk Score

Malware Insights

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

The PDF contains multiple embedded links, with at least one pointing to known malicious redirector infrastructure. The ML classifier and ClamAV detection strongly indicate malicious intent. The document body, though heavily obfuscated, suggests a lure related to learning materials, likely to trick users into clicking the malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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/aws?utm_term=learn+html+full+course+in+hindi In PDF document text
    • https://cdn.sqhk.co/fugovigul/9ghJgiI/gomugipati.pdfIn PDF document text
    • https://cdn.sqhk.co/gukugifixija/ijER8ib/62185162237.pdfIn PDF document text
    • https://wosobariwosamu.weebly.com/uploads/1/3/4/3/134372044/nuxodikuk.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4366325/normal_5fdaf00b58b09.pdfIn PDF document text
    • https://jejenovo.weebly.com/uploads/1/3/1/4/131454593/dugevig.pdfIn PDF document text
    • https://cdn.sqhk.co/dodalowogiv/cVggicp/55526323124.pdfIn PDF document text
    • http://rozujed.sportsontheweb.net/discipline_equals_freedom_book_depository.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4489852/normal_600cf5353b950.pdfIn PDF document text
    • https://gebijodefilamoz.weebly.com/uploads/1/3/1/4/131406109/fb03c4ec70.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4470205/normal_5fc6217667a20.pdfIn PDF document text
    • https://virutabadipepuv.weebly.com/uploads/1/3/1/3/131398083/841f8473ca27b.pdfIn PDF document text
    • https://basitonivi.weebly.com/uploads/1/3/4/5/134584834/7341701.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://wotidupodugi.myartsonline.com/nururogirotu.pdfIn PDF document text
    • https://s3.amazonaws.com/pulavokaxe/usgs_quad_maps.pdfIn PDF document text
    • http://pabewuvuxaf.onlinewebshop.net/11309916913.pdfIn PDF document text
    • https://s3.amazonaws.com/wizuluworafid/template_cv_simple_indonesia.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_off0000e29d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE29D 5200 bytes
SHA-256: f83dabc35654b1782469bd577a1a3fb8b8450517bbb4ebe7caaa9f15a3fbdccd
font_01_sfnt_off0000f428.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF428 10256 bytes
SHA-256: 5a82dcf260cf01c5adef54ea3aeb126908c456edafd242f18ad8b67c316a2576

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