Malicious PDF — malware analysis report

Static analysis result for SHA-256 31729ca326780047…

MALICIOUS

PDF

79.6 KB Created: 2021-02-12 04:06:59 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-23
MD5: f0ec30b684d30033f539086b9d2417ca SHA-1: 3180f9077869fcca4ab0e954837d1eec913962b3 SHA-256: 31729ca3267800478e0b9f47544ac0be7380428f8aec75193749c0619530924e
186 Risk Score

Malware Insights

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

This PDF file exhibits characteristics of a phishing lure, as indicated by the 'Excuse letter for school absence because of sick' content and the presence of numerous external links. The ML classifier and ClamAV detection strongly suggest malicious intent, likely to redirect users to phishing or malware distribution sites. The PDF_SEO_LINK_FARM heuristic indicates a large number of external links, many pointing to disposable hosting, further supporting the phishing/malware distribution hypothesis.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://jottigo.ru/123?utm_term=excuse+letter+for+school+absence+because+of+sick PDF link annotation
    • https://static.s123-cdn-static.com/uploads/4425515/normal_5fe01c548c306.pdfIn PDF document text
    • https://cdn.sqhk.co/vekuperik/7PVggpN/parrot_wallpaper_hd_4k.pdfIn PDF document text
    • https://cdn.sqhk.co/lewoxiguj/rhfhhhe/never_have_i_ever_dirty_edition_instagram.pdfIn PDF document text
    • https://fodigedij.weebly.com/uploads/1/3/2/7/132740281/fuwiv-tevurile-fezas-dabegemigugi.pdfIn PDF document text
    • https://jimivisimobud.weebly.com/uploads/1/3/4/9/134901817/45a243.pdfIn PDF document text
    • https://duniterete.weebly.com/uploads/1/3/4/6/134690204/sitopi_gelugelezit_sakapozemi_losijebi.pdfIn PDF document text
    • https://kemigaguni.weebly.com/uploads/1/3/1/0/131070112/4177556.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4443371/normal_601c650e508d9.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4476274/normal_6011810a030f6.pdfIn PDF document text
    • https://manumuxalobo.weebly.com/uploads/1/3/5/3/135387638/e5136012d3e758e.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4425908/normal_5fe3bb94b7f52.pdfIn PDF document text
    • https://ledajesaler.weebly.com/uploads/1/3/4/0/134041179/16d4de41c5.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4473047/normal_5fda538bc4316.pdfIn PDF document text
    • https://momimuraw.weebly.com/uploads/1/3/1/3/131384495/lelefigud.pdfIn PDF document text
    • https://cdn.sqhk.co/develezuwa/b7lwidj/vifesukisebujibesufaf.pdfIn PDF document text
    • https://pirulavedup.weebly.com/uploads/1/3/1/3/131379447/d75ac5.pdfIn PDF document text
    • https://cdn.sqhk.co/fegujajox/ge6JNkC/rochester_mi_school_calendar_2020.pdfIn PDF document text
    • https://malitizume.weebly.com/uploads/1/3/4/0/134097131/sebejifu_fakividewis.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn 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_off0000f928.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF928 5200 bytes
SHA-256: dc5518c9c502a051a2192d9518527a9c2fbf7b1019cd488ed8c2aed90a0917b9
font_01_sfnt_off00010ad4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10AD4 11272 bytes
SHA-256: 75c52bd2c505b9881fab4ee4d8de1d3fa0a191350a027ca66c6ee52ace8b71c8

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