Malicious PDF — malware analysis report

Static analysis result for SHA-256 c935bb4e6c5b76df…

MALICIOUS

PDF

78.2 KB Created: 2021-03-23 09:12:07 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-21
MD5: 7b84db2d818c1ad0036705f6093c2251 SHA-1: f04df3ce4b2250facc436234758714b90d958916 SHA-256: c935bb4e6c5b76df724d4807fe55813efc033e3f1f4496db51ae4aeae02baadd
186 Risk Score

Malware Insights

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

The PDF file was flagged by multiple heuristics as malicious, including a critical ClamAV detection and an ML classifier indicating a high probability of maliciousness. It contains a significant number of external links, many pointing to disposable hosting, suggesting a link farm or SEO spam operation. The presence of embedded URLs and the nature of the heuristics strongly indicate an attempt to redirect users to malicious or phishing sites.

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://pelibifir.ru/123?utm_term=phospholipids+form+bilayers+in+water+because PDF link annotation
    • https://static.s123-cdn-static.com/uploads/4446507/normal_6007152b665f0.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4365589/normal_5fd1cdf7b1c10.pdfIn PDF document text
    • https://menerixejujup.weebly.com/uploads/1/3/4/6/134605313/6780283.pdfIn PDF document text
    • https://silavetej.weebly.com/uploads/1/3/5/3/135314504/pevaxivi.pdfIn PDF document text
    • https://nejajabowiwuxo.weebly.com/uploads/1/3/0/7/130775705/7406395.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4485149/normal_603c3bb2ed832.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4468534/normal_5fded5961380a.pdfIn PDF document text
    • https://gukaguse.weebly.com/uploads/1/3/1/3/131398473/6c4d06.pdfIn PDF document text
    • https://kujibolivobukib.weebly.com/uploads/1/3/1/1/131163991/6681050.pdfIn PDF document text
    • https://tonituligavu.weebly.com/uploads/1/3/4/8/134884188/1313b27da388.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4416327/normal_5fdb2242e747d.pdfIn PDF document text
    • https://vimiwegom.weebly.com/uploads/1/3/0/7/130775837/1958775.pdfIn PDF document text
    • https://gororumemi.weebly.com/uploads/1/3/4/5/134517819/8ff67.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4393489/normal_6035aebe96914.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/dinilederu/the_american_heritage_college_dictionary_4th_edition.pdfIn PDF document text
    • https://s3.amazonaws.com/bagokiko/virtual_tabletop_assets_dd_beyond_integration.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/e90f69f0-bbda-4851-b5b9-57d477a0166a/q_see_presidio_login.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/de37bd97-69fd-4980-839f-b68d068ea932/jump_force_pc_all_characters_unlocked.pdfIn PDF document text
    • https://s3.amazonaws.com/wotodedaruzuk/what_is_student_engagement_and_why_is_it_important.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/617fc035-7cdf-464a-9d15-193386a4a249/kenmore_mini_fridge_and_freezer.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_off0000f15c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF15C 5728 bytes
SHA-256: 0079a66ab870a5fde7b210bc1b1429bff67c228ccd53e33ca53dfee46b56f8d9
font_01_sfnt_off000104c4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x104C4 10872 bytes
SHA-256: cfd31a4237d8eb1dc4af37ff713f68381e714439dc4252adad12808707b54aa3