Malicious PDF — malware analysis report

Static analysis result for SHA-256 81372bf51141bac4…

MALICIOUS

PDF

77.0 KB Created: 2021-03-18 22:39:11 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-25
MD5: 38d3eee3b4cd6fdd68ce0eba05c5c63b SHA-1: 8b116b0fcdc5f4ae630f283911a7f161ab6ef134 SHA-256: 81372bf51141bac41842d5841f2e8cb900ef177d5c3c5b0d782b01e0c5b73097
134 Risk Score

Malware Insights

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

This PDF document was flagged as malicious by an ML classifier. It uses an invoice-themed lure. The file embeds a large number of external links characteristic of an SEO link farm. Specific URLs and indicators for this sample are listed in the indicators section.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

Heuristics 6

  • 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.
  • Fake invoice / payment lure low SE_INVOICE_LURE
    Document contains invoice or payment language paired with an action verb — useful context when combined with link, macro, or attachment indicators
  • 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://bologen.ru/123?utm_term=free+bookkeeping+ledger+template PDF link annotation
    • https://sudororurupe.weebly.com/uploads/1/3/4/6/134602833/87b739577e07b.pdfIn PDF document text
    • https://gizutiki.weebly.com/uploads/1/3/4/4/134478998/1999806.pdfIn PDF document text
    • https://xutativapejan.weebly.com/uploads/1/3/4/5/134521393/9616277.pdfIn PDF document text
    • http://skidki-day.store/how_to_find_the_magnitude_of_gravitational_forcejfh1y.pdfIn PDF document text
    • http://paxosij.mygamesonline.org/sorub.pdfIn PDF document text
    • http://fullpisetc.ru/70825022845biae5.pdfIn PDF document text
    • https://wasutemup.weebly.com/uploads/1/3/4/6/134651280/9559458.pdfIn PDF document text
    • http://streamsweets.com/39312370235nm0dl.pdfIn PDF document text
    • https://ximusufupes.weebly.com/uploads/1/3/4/4/134486044/latop.pdfIn PDF document text
    • http://wopizup.mypressonline.com/63880226170.pdfIn PDF document text
    • http://b4shop.icu/929556297740ogll.pdfIn PDF document text
    • https://rapovadok.weebly.com/uploads/1/3/4/7/134705404/fusero.pdfIn PDF document text
    • http://wei-nmvc.com/26344566464vrpoi.pdfIn PDF document text
    • https://ramitafot.weebly.com/uploads/1/3/4/3/134340854/70113.pdfIn PDF document text
    • https://fewabupa.weebly.com/uploads/1/3/4/5/134584226/burarusubexufig.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://d497f082-4895-42de-a72c-038d9367c8a3.filesusr.com/ugd/8e727b_5917b5924c414d59ae63ec1dcd865810.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/ee2f57e0-0d87-4399-a11b-e090e86850a8/fatut.pdfIn PDF document text
    • https://98e80eac-0673-4bf9-a3de-4132461903b3.filesusr.com/ugd/1acd69_6c0e78bfe6c4460e9efb1d3b50f814a8.pdf?index=trueIn PDF document text
    • https://dc273c12-e125-4738-b2e6-b96bc4bd5eb7.filesusr.com/ugd/c8df25_8e363617a2064b0da84f211443e736e5.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/501729d3-a28f-4a5e-963c-1167deddb1f0/c_programming_absolute_beginners_guide_amazon.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/30b57a1b-a448-4be1-83de-177f3cf222c4/bowflex_m5_for_sale.pdfIn PDF document text
    • https://7ae52be2-ba3c-41fb-8935-29281088223e.filesusr.com/ugd/affaa6_3e3d37c755e34b7985e7deabd85faa7e.pdf?index=trueIn PDF document text
    • https://3c199e1c-ff83-4553-a351-db1e9419129c.filesusr.com/ugd/424a74_0385754d991942338786ac4941e633b2.pdf?index=trueIn PDF document text
    • http://zupitatip.atwebpages.com/doxefipivozaxodi.pdfIn PDF document text
    • http://tivakifuzir.atwebpages.com/52323852144.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_off0000f0cf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF0CF 5260 bytes
SHA-256: d60bbb3526552a12b2c03d2f4b0a5b7cd22f5cd5ed8b72af9d96350e01e6b636
font_01_sfnt_off0001029f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1029F 10504 bytes
SHA-256: aa8c41218c824ae8c349f34da9aa2b985d67eeffc5dc5f48ce075c85a4c66848