Malicious PDF — malware analysis report

Static analysis result for SHA-256 5f3895f705ffe4d3…

MALICIOUS

PDF

45.0 KB Created: 2020-08-19 22:47:45 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 8dd641a5207ea5b5a74f84a512a6afe6 SHA-1: c715031dc8d5dc341dc1d0ecb4d96ac74cfb9f48 SHA-256: 5f3895f705ffe4d3f870277bfc98584c92204869a22f2571f71f5e50eea29597
154 Risk Score

Malware Insights

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

The PDF contains numerous links to external PDFs, with one specifically pointing to a known malicious redirector. The document body, though obfuscated, contains text related to subtraction worksheets and also embeds the malicious URL, suggesting a lure to disguise malicious activity. The ML classifier strongly indicates maliciousness, and the presence of embedded URLs points towards a phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 4

  • 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.
  • 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://ttraff.com/pify?keyword=two+digit+subtraction+with+regrouping+worksheets+pdf
    • http://files.privatetourssanfrancisco.com/uploads/1/3/1/3/131384429/nomamodezenawi-wujidibimik.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • http://www.daltonmaag.com/
    • https://cdn.shopify.com/s/files/1/0429/7211/9193/files/durifutefegukavumila.pdf
    • https://cdn.shopify.com/s/files/1/0432/6014/9910/files/44145907078.pdf
    • https://cdn.shopify.com/s/files/1/0432/7686/1606/files/nugukusufunisizik.pdf
    • https://cdn.shopify.com/s/files/1/0429/2732/5343/files/xutiparomuviwuwem.pdf
    • https://cdn.shopify.com/s/files/1/0431/0522/2822/files/95828787902.pdf
    • https://cdn.shopify.com/s/files/1/0437/5996/0218/files/paralegal_billable_hours_template.pdf
    • https://cdn.shopify.com/s/files/1/0437/2555/3815/files/27075658900.pdf
    • https://cdn.shopify.com/s/files/1/0433/9377/7827/files/71020390162.pdf
    • https://cdn.shopify.com/s/files/1/0429/5891/3689/files/71775831411.pdf
    • https://cdn.shopify.com/s/files/1/0437/8024/3617/files/calculus_and_its_applications_13th_edition_download.pdf
    • https://cdn.shopify.com/s/files/1/0431/5283/4717/files/67387958459.pdf
    • https://cdn.shopify.com/s/files/1/0431/7777/1164/files/47282435829.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://scripts.sil.org/OFL

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off000062a0.bin
f5f1b3d7090d302668376419a1d38cfc58b7e08ece2d002642258c9831dedda8		 pdf-font-stream PDF embedded font (sfnt) at offset 0x62A0 5512 bytes
font_01_sfnt_off00007567.bin
6c35dc257c96b7a7f564dbd6ca4a346b086922f4691daf8fd056b4f5ef6cc4bd		 pdf-font-stream PDF embedded font (sfnt) at offset 0x7567 10212 bytes
font_02_sfnt_off0000984e.bin
b50a2106bf82917db0cd3cf88f63c5e8cc3298b343ace5cffc591b35df33d24c		 pdf-font-stream PDF embedded font (sfnt) at offset 0x984E 4324 bytes

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