Malicious PDF — malware analysis report

Static analysis result for SHA-256 3a959a51836e329f…

MALICIOUS

PDF

76.9 KB Created: 2021-04-01 20:26:54 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-20
MD5: a2d9e1bc03f294149c818fc808fd5b74 SHA-1: 70d6bf45efa2642715becaf00a5246b0878896f2 SHA-256: 3a959a51836e329f68770726570be256c65fb41062ec21d9a15e0876c054c734
186 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1105 Ingress Tool Transfer

The PDF file contains numerous external links, indicating it functions as a link farm. Heuristics like 'PDF_SEO_LINK_FARM' and 'PDF_SEO_DISPOSABLE_LINK_FARM' strongly suggest this behavior, with many links pointing to disposable or potentially malicious hosting. The ClamAV detection and ML classifier further support its malicious nature, likely for SEO spam or to distribute further malware. The embedded URLs are the primary indicators of compromise.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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
  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • 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://jacksth.ru/award?keyword=elementos+de+matematica+nicolas+bourbaki+pdf PDF link annotation
    • https://butemupow.weebly.com/uploads/1/3/5/3/135338881/mizisir.pdfIn PDF document text
    • https://pobivizitonep.weebly.com/uploads/1/3/2/8/132815986/9677813.pdfIn PDF document text
    • http://bapulesaj.mygamesonline.org/dcouper_a3_en_2_a4.pdfIn PDF document text
    • http://mufinofol.scienceontheweb.net/56737652170.pdfIn PDF document text
    • https://vemakovuzabomon.weebly.com/uploads/1/3/4/8/134881214/b9227f.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4484805/normal_5fd611bb5de4b.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4409796/normal_602bf8c2b82a6.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4390052/normal_601835ae6f6ee.pdfIn PDF document text
    • http://tarusexozof.iblogger.org/ansys_apdl_training.pdfIn PDF document text
    • https://sanituwinera.weebly.com/uploads/1/3/1/3/131379206/3903388.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4470677/normal_602cb1f2aac45.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4453740/normal_5ffbc91252868.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://f8b2de7a-6012-4721-b8f1-df5267d6bb95.filesusr.com/ugd/8ebb60_fbf25fa0da244abeb8e87cb3bfd1111d.pdf?index=trueIn PDF document text
    • http://luxizetugo.epizy.com/tikizibite.pdfIn PDF document text
    • https://74bb8966-1fc2-43cb-a641-24c20f380d28.filesusr.com/ugd/84c7b5_0fbf0865054744a6833785addeab24f0.pdf?index=trueIn PDF document text
    • https://ea74ff18-003d-4094-8454-8d7e15e33abb.filesusr.com/ugd/50de67_9aca5790fd4646b5825cc339676f1645.pdf?index=trueIn PDF document text
    • http://dowegumorugujon.epizy.com/vuzabuta.pdfIn PDF document text
    • https://s3.amazonaws.com/gagotaniwipure/bonikosij.pdfIn PDF document text
    • https://dbb1fad9-9c05-458f-9e32-bc0b7f65d7ec.filesusr.com/ugd/451461_dfb5265d29394e4c95640423e5aadd74.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/bokelur/how_to_do_subtraction_in_vedic_maths.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_off0000e8bf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE8BF 5460 bytes
SHA-256: 194c19e6148262c24d4bbee5b18e25391b2baca6c06256aa951f151167f91251
font_01_sfnt_off0000fb39.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFB39 12968 bytes
SHA-256: 5d846f761758e24684c54ee71662d928ddd0adfd12a29cb78e5ee4f1fa1f1b41

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