Malicious PDF — malware analysis report

Static analysis result for SHA-256 61aaa3e30dcbb778…

MALICIOUS

PDF

47.3 KB Created: 2020-10-04 18:47:01 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-26
MD5: 78d8e2fcaf2c2ac48def24cb28603b76 SHA-1: eebbe40037cee134e0d5a53efee147fe7fc6049c SHA-256: 61aaa3e30dcbb7780c1121f8f8bd9b4ce41614700b0492b6b2474c3086a722fe
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 other PDF files hosted on disposable domains. One of these links, https://cctraff.ru/strik?keyword=c1+exam+cambridge+pdf, is identified as a malicious redirector. The document's primary function appears to be acting as a link farm to distribute malicious content or lead users to phishing sites.

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=c1+exam+cambridge+pdf In PDF document text
    • https://site-1037111.mozfiles.com/files/1037111/71813957565.pdfIn PDF document text
    • https://site-1036972.mozfiles.com/files/1036972/29560737511.pdfIn PDF document text
    • https://site-1036637.mozfiles.com/files/1036637/dojiregivul.pdfIn PDF document text
    • https://site-1036731.mozfiles.com/files/1036731/85454577075.pdfIn PDF document text
    • http://zubajanep.twinfallslivestock.com/uploads/1/3/0/7/130776138/f7784.pdfIn PDF document text
    • http://nogogax.autumnserenityhealing.com/uploads/1/3/1/4/131437601/7358986.pdfIn PDF document text
    • http://pajezanir.febinteriors.com/uploads/1/3/1/8/131871456/pufufogoba_dasesodaxebi_xatunex.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://cdn.shopify.com/s/files/1/0479/6861/6604/files/nititoxamodevakererotid.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0496/6121/4877/files/18522700357.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/49789f51-ad0d-4fe7-b41e-05c728b9d3d7/38012244055.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/7fdb35a5-ffe0-4c62-9faa-88fc4e48e485/vizusomuxuvibojo.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/412d0524-7661-45d0-a139-0847e7a0d001/74802149748.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/29847f6d-e27a-420a-b13a-463ecbff5978/99369761283.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_off00007a96.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x7A96 5432 bytes
SHA-256: a943246c316e0265bc8195bcb42a652d99cf6e373e91adabe68da3367f8c86de
font_01_sfnt_off00008d00.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x8D00 10520 bytes
SHA-256: 26067503d94a2a1661b35dc89476c68cc01fb7b54daacf66eab1aa3fd8b3e6d5

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