Malicious PDF — malware analysis report

Static analysis result for SHA-256 238748c37feb4e64…

MALICIOUS

PDF

71.7 KB Created: 2021-03-07 03:30:14 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-23
MD5: 6d1f3fc7f147f723c5c12c201f120d18 SHA-1: e174000534158304da6bb90a401bb0f938aa19e6 SHA-256: 238748c37feb4e64c83b3ee1ff4ab6c1a209930789adae4ae1f2aead7256957b
186 Risk Score

Malware Insights

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

The PDF contains numerous external links, many pointing to disposable hosting, and uses a deceptive title related to a Microsoft keyboard setup. This strongly suggests a phishing or malware distribution lure. The ClamAV detection and ML classifier output further support its malicious nature. No scripts were extracted, but the PDF structure itself facilitates the redirection to malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://jottigo.ru/strik?utm_term=microsoft+sculpt+comfort+keyboard+setup PDF link annotation
    • https://cdn.sqhk.co/bozutebux/eijGjcu/piano_keyboard_game_offline.pdfIn PDF document text
    • https://cdn.sqhk.co/fusojafiza/ipgfiad/mafezurudobo.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://s3.amazonaws.com/pegebunov/butek.pdfIn PDF document text
    • https://f238abdf-92e3-4651-90df-65b6e8a648d9.filesusr.com/ugd/99965f_a2b9f1796e174267a7483c881251aac2.pdf?index=trueIn PDF document text
    • https://b3d988c2-7a7d-4c3c-9141-221b6550481e.filesusr.com/ugd/9dda13_156401bde75441fe82eb8e9908e5915f.pdf?index=trueIn PDF document text
    • https://6bfd3344-23d3-4e03-ab7d-00c1c23eecf6.filesusr.com/ugd/be19e1_291c547d12204383acd9d7ae29e170ac.pdf?index=trueIn PDF document text
    • https://aa4de0c4-a7fb-47f6-97fe-5721705e71c1.filesusr.com/ugd/824332_324ceb5c82ca4aa892934f368aeeb5ff.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/xokebore/printable_vocabulary_worksheets_for_6th_grade.pdfIn PDF document text
    • https://627f215e-41ba-4aa4-9906-5f9f9d117739.filesusr.com/ugd/8ab72e_05ce91d26b1a4d4da91234fdd2e469d8.pdf?index=trueIn PDF document text
    • https://78e27e65-9996-4239-a63d-7a21722db537.filesusr.com/ugd/03f576_29549dd535df422db47ca9bd81af9485.pdf?index=trueIn PDF document text
    • https://6e37e838-c278-4d46-baa9-25b8497af200.filesusr.com/ugd/fbcb80_4b93d2a06b3648548840cdc4a5e60e18.pdf?index=trueIn PDF document text
    • https://e8677ced-6330-435e-8237-200fb10408a4.filesusr.com/ugd/a4c1fa_2c05750bbba44ce7959c322e0a45c39e.pdf?index=trueIn PDF document text
    • https://2dc0326d-ac60-47d8-bf46-f2dc9d334570.filesusr.com/ugd/21b4a7_d03d9b04bf284d57b8bc29ac38aac5b4.pdf?index=trueIn PDF document text
    • https://e5b7f393-9b83-42c5-a877-5b85c0c772c8.filesusr.com/ugd/77b42d_3ba94cc3a97443e1a7a1efeaa14d1ace.pdf?index=trueIn PDF document text
    • https://6998e30b-c911-4113-ab34-4c15204891c7.filesusr.com/ugd/429b25_125c6fef8dfe4961bbe65044284706d5.pdf?index=trueIn 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_off0000db84.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDB84 5612 bytes
SHA-256: 401fa9dde2c5b22956a76f3c2dddc69fa81cb807e71c9823431d48b94b22d94e
font_01_sfnt_off0000ee96.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEE96 10252 bytes
SHA-256: 521d1e930e321b86d9b6407d43006b6879c8260270b5980139d808e49cf2fbe0