Malicious PDF — malware analysis report

Static analysis result for SHA-256 a9ba4590b0d442b7…

MALICIOUS

PDF

40.6 KB Created: 2020-10-07 00:52:13 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-22
MD5: 8a4348d9263203112f83919d49becc3f SHA-1: cff3a7938de3d2abd79e3631425c2ea49c91126a SHA-256: a9ba4590b0d442b70a60002c50adec46a0932e2357abf029171e8e5626ac014e
184 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF file contains a large number of embedded links, many of which point to external PDF files hosted on disposable domains. The primary URL, https://cctraff.ru/strik?keyword=adding+and+subtracting+roman+numerals+worksheet+pdf, suggests a lure related to educational worksheets, likely to trick users into clicking through. The heuristic firings indicate this is a malicious redirector and a link farm designed for SEO manipulation, potentially distributing further malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 5

  • PDF links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK
    PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
  • 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.
  • 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://cctraff.ru/strik?keyword=adding+and+subtracting+roman+numerals+worksheet+pdf In PDF document text
    • http://warubag.laralindphoto.com/uploads/1/3/2/6/132681862/7004336.pdfIn PDF document text
    • http://files.achildwaits.org/uploads/1/3/0/7/130740231/bokatiwaxuzutebo.pdfIn PDF document text
    • http://lasif.colorsofthewindhorsefarm.com/uploads/1/3/1/0/131069910/34976a61.pdfIn PDF document text
    • http://files.turbobeads.com/uploads/1/3/2/3/132303245/nunusi.pdfIn PDF document text
    • http://wotenulug.placercountyreviewagency.com/uploads/1/3/1/6/131636733/jiruxus.pdfIn PDF document text
    • http://files.ronaldvanloon.nl/uploads/1/3/1/4/131407535/visidarolotep_duzixowi_juxonika_peweri.pdfIn PDF document text
    • http://files.krittermall.com/uploads/1/3/1/8/131856209/2417472.pdfIn PDF document text
    • http://rakivozuk.newamsterdamny.org/uploads/1/3/0/9/130969352/mafodofafejojoji.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://uploads.strikinglycdn.com/files/130f70c1-72b9-4f87-923b-bcfa491c436f/14860025939.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0481/6771/4983/files/napeluk.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0480/9044/8035/files/44681489244.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0462/6720/3733/files/minecraft.jar_download_linux.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_off00005f33.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x5F33 5856 bytes
SHA-256: 59ef157a455d64c22c918e0808001bb489ff24adcaceb2d4b827f7578f8f63e7
font_01_sfnt_off0000730a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x730A 10144 bytes
SHA-256: fb0d6e62e9a7440872a873c73b36aca4884d2b3b17cdc464cf7df95a514594d6

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