Malicious PDF — malware analysis report

Static analysis result for SHA-256 b235a3cafe29c3ab…

MALICIOUS

PDF

36.4 KB Created: 2020-10-10 23:14:13 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-23
MD5: 73efa00ef0228b2643cd5bf94870143f SHA-1: fb615604d04eaab25308966dd489e4a7adab97b1 SHA-256: b235a3cafe29c3abffef905add405452c85ecbe5192b133b09151caac8197941
184 Risk Score

Malware Insights

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

The PDF contains a large number of embedded links, many of which point to disposable hosting and redirector infrastructure. One critical heuristic identified a link to known malicious redirector infrastructure at https://cctraff.ru/strik?keyword=watch+cheaper+by+the+dozen+free. The document body, though heavily obfuscated, also contains this URL and other PDF links, suggesting a lure to entice users to click through to potentially 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=watch+cheaper+by+the+dozen+free In PDF document text
    • http://files.cr8blk.org/uploads/1/3/2/6/132695701/00944.pdfIn PDF document text
    • http://files.annmaglinte.com/uploads/1/3/1/8/131856427/4d0d60.pdfIn PDF document text
    • http://files.las-core.com/uploads/1/3/1/6/131606069/967dae5.pdfIn PDF document text
    • http://gopav.davidthany.com/uploads/1/3/1/4/131452836/383867.pdfIn PDF document text
    • http://files.londonsetterby.com/uploads/1/3/2/6/132681558/vuvopuse.pdfIn PDF document text
    • http://files.sunnysidesymphony.org/uploads/1/3/1/8/131872042/13e737.pdfIn PDF document text
    • http://muranezum.onandofftheroadcreativeimages.com/uploads/1/3/1/4/131406118/titaruvat_debimulebip_davoxonafugisir_ganexede.pdfIn PDF document text
    • http://files.lesproductionstechnodenis.com/uploads/1/3/0/8/130814448/jakuzanu.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/6567214a-409b-4033-984f-36da2bd93c05/kajatigiweteju.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/d0f509e5-47fa-4747-bb07-d4a833919e48/89045723514.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/fdc06cbb-d5b3-47fd-987d-93e718c83330/mavifupeno.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/1123c3d8-3270-45b5-a0c5-5e0237c37173/85012287546.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/8ecc285c-8eee-42f3-9639-fe03e255587b/wemajerebogojidu.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0431/6453/2900/files/pafovojinepajaruwinonejob.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0495/9102/5827/files/15682979602.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_off00004f88.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x4F88 5340 bytes
SHA-256: beabad4d19e634d756fa0f5ae36e8353b75ead830be192c43fd478dff30a75cc
font_01_sfnt_off000061b9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x61B9 10416 bytes
SHA-256: 5f5bcee25c33c3d333719d1e8aebc1099e70415511d16655bef534bd3ad60291

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