Malicious PDF — malware analysis report

Static analysis result for SHA-256 b1f7e506726709a9…

MALICIOUS

PDF

79.9 KB Created: 2021-06-07 00:25:27 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: e470632adc6e86d440782b61744ea7f4 SHA-1: a1f172ad04716db8e1eab2d8d70a89120e0bf118 SHA-256: b1f7e506726709a967b7363c90ae1a153b35e7e5d933edc19e4892801bdd0586
126 Risk Score

Malware Insights

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

The PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous embedded URLs, many pointing to disposable hosting, and is flagged as a link farm designed to redirect users. The document body, though heavily obfuscated, suggests a lure related to 'free math worksheets grade 6 fractions', which is a common tactic for phishing or malware distribution. No scripts were extracted, but the presence of external URIs and the link farm heuristic strongly suggest the PDF is a delivery mechanism for malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • 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 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://crophysi.ru/123?utm_term=free+math+worksheets+grade+6+fractions
    • https://lexobazotukagof.weebly.com/uploads/1/3/1/4/131407042/wagoduximisozegupigu.pdf
    • https://bevalulage.weebly.com/uploads/1/3/4/9/134902231/975a5591ac.pdf
    • https://cdn-cms.f-static.net/uploads/4486548/normal_6035b3349e6e7.pdf
    • https://static.s123-cdn-static.com/uploads/4452199/normal_5ffe09050a52b.pdf
    • https://vibokijejegol.weebly.com/uploads/1/3/4/7/134756418/sixalisasesumufus.pdf
    • https://static.s123-cdn-static.com/uploads/4370286/normal_5ffa354f66740.pdf
    • https://mefinijusigoti.weebly.com/uploads/1/3/4/4/134499215/763c79fd04.pdf
    • https://cdn-cms.f-static.net/uploads/4460980/normal_604eb26ae3b34.pdf
    • https://cdn-cms.f-static.net/uploads/4380078/normal_6065205e96625.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • http://www.daltonmaag.com/
    • http://wezenibafasi.pbworks.com/f/65274574704.pdf
    • http://sejiliki.pbworks.com/w/file/fetch/144669768/formula_para_calcular_el_punto_de_equilibrio_en_economia.pdf
    • http://xojifot.pbworks.com/f/super_smash_flash_2_unblocked_663.pdf
    • http://fokojifidesi.pbworks.com/f/how_hard_is_the_aapc_cpc_exam.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://scripts.sil.org/OFL

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ed16.bin
b871208d2fe473507f5feb5b85ed11fdcfcb528bf7c435ed43cb7a7e10676d4f		 pdf-font-stream PDF embedded font (sfnt) at offset 0xED16 5456 bytes
font_01_sfnt_off0000ff93.bin
8be1babe8d32110048ab764c1cb13fa6eabf28656b8ef301fbdb8908201f8d7e		 pdf-font-stream PDF embedded font (sfnt) at offset 0xFF93 10936 bytes
font_02_sfnt_off000124e3.bin
ff5f0ef16caf3e97cd1984b3a03ea88e11eab8cf63d2ee006085a4b9995833f3		 pdf-font-stream PDF embedded font (sfnt) at offset 0x124E3 4324 bytes

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