Malicious PDF — malware analysis report

Static analysis result for SHA-256 21a86cb8e8f186f8…

MALICIOUS

PDF

36.0 KB Created: 2020-10-09 11:28:47 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-23
MD5: d20a3dccd5426d3da589e87ae6414883 SHA-1: 71a96eba3c5c03482d332c6cd0d191e01d05c0a9 SHA-256: 21a86cb8e8f186f81fbe4d11ac0b33e33d29e517598a5bd1c2644323ec42e114
184 Risk Score

Malware Insights

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

The PDF contains a large number of links to external PDFs hosted on various domains, many of which appear to be disposable. One critical heuristic firing indicates a link to known malicious redirector infrastructure, suggesting a phishing or malware distribution attempt. The ML classifier also strongly flagged this PDF as malicious.

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://ggtraff.ru/strik?keyword=curious+george%253A+a+very+monkey+christmas In PDF document text
    • http://files.ensemblemusicahumana.com/uploads/1/3/0/9/130969545/zusodevivi.pdfIn PDF document text
    • http://neninenol.thenakedforge.com/uploads/1/3/0/8/130814173/5677366.pdfIn PDF document text
    • http://wazavag.tccschattanooga.com/uploads/1/3/1/0/131070152/dewidewo_kabapinizal_nukuzonavulelen.pdfIn PDF document text
    • http://rusujudo.garytwynam.com/uploads/1/3/0/9/130969426/dotubizezinowe.pdfIn PDF document text
    • http://semud.rivelazioniprivate.org/uploads/1/3/0/8/130873863/tatagelere.pdfIn PDF document text
    • http://kunevipu.atomysupport.com/uploads/1/3/1/4/131406121/d990f863701.pdfIn PDF document text
    • http://files.applebypropertymanagement.com/uploads/1/3/1/4/131454355/b4b32c97f.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/1/0482/3223/5160/files/92498227260.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0433/1202/1662/files/tarujani.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0496/0377/2565/files/madden_nfl_16_apk_download.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/772dc1e8-6118-4729-b6ef-a37efe36e72c/9378091212.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/f091ada9-d516-4b55-9e7b-0a180b496840/xizagarad.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/952465ef-c584-4eac-9c47-516e1d70f384/vefojizobagilewe.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/395d8344-ed83-4f04-8841-2740cd73dce8/6182018394.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_off00004cb5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x4CB5 5364 bytes
SHA-256: 8b49da1d4901255eb0ebece360d5d05960af6a1da27fee7d726c3d666c95aa28
font_01_sfnt_off00005edc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x5EDC 10620 bytes
SHA-256: db5a8c7b2dafbb509e059d0b8478f05f3fcf23ba6a38b4ca00ec9885c1c7c815

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