Malicious PDF — malware analysis report

Static analysis result for SHA-256 81fb8b5ff6bddbad…

MALICIOUS

PDF

42.9 KB Created: 2020-08-08 00:56:05 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 15c3b307333c4a5cc0a06e77a2941b30 SHA-1: 61e4b83e94599885854ec0ef85525cc5c92e65e0 SHA-256: 81fb8b5ff6bddbad2258c9feaeb8dc5ecd0078c5da8fd057651f68c195f49835
162 Risk Score

Malware Insights

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

The PDF contains a critical heuristic firing for linking to known malicious redirector infrastructure, specifically `https://ttraff.cc/pify?keyword=langman+s+medical+embryology+13+pdf`. It also exhibits characteristics of a PDF link farm, with numerous embedded links to other PDFs, many hosted on Shopify. The presence of a 'download button' lure and the ML classifier's high confidence further support its malicious nature. The document body, though heavily obfuscated, contains URLs that are likely part of this link farm, suggesting an attempt to lure users to malicious content under the guise of providing documents.

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.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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.cc/pify?keyword=langman+s+medical+embryology+13+pdf
    • http://files.jameshuntermusic.com/uploads/1/3/1/0/131070526/sevaziwedonebela.pdf
    • http://files.mountainspiritswellness.com/uploads/1/3/1/0/131069906/sozakukowux-kinotowikik.pdf
    • http://files.cedarridgeupnorth.com/uploads/1/3/1/8/131871390/802040c946.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://cdn.shopify.com/s/files/1/0436/8941/0713/files/zuvifaxudemesixugosaf.pdf
    • https://cdn.shopify.com/s/files/1/0432/6499/9590/files/bronnie_ware_libro.pdf
    • https://cdn.shopify.com/s/files/1/0435/9805/3535/files/xelojeleku.pdf
    • https://cdn.shopify.com/s/files/1/0445/6746/2047/files/financial_accounting_ratios.pdf
    • https://cdn.shopify.com/s/files/1/0431/6754/7552/files/15050984977.pdf
    • https://cdn.shopify.com/s/files/1/0436/1961/4884/files/76060164287.pdf
    • https://cdn.shopify.com/s/files/1/0437/3594/1274/files/mifolebi.pdf
    • https://cdn.shopify.com/s/files/1/0431/0519/0041/files/the_iliad_with_line_numbers.pdf
    • https://cdn.shopify.com/s/files/1/0432/5595/5619/files/midewupisodafepe.pdf
    • https://cdn.shopify.com/s/files/1/0437/2342/3912/files/17159995581.pdf
    • https://cdn.shopify.com/s/files/1/0433/6913/6284/files/womoxepa.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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00005f4b.bin
d0c4f2678af593dcc770e306ab46a69c493efbe52ff11d59d3691c4b18af27b9		 pdf-font-stream PDF embedded font (sfnt) at offset 0x5F4B 5876 bytes
font_01_sfnt_off00007346.bin
3a3deca9a048438ad346e9b7184c01dc3c11abde1964886050fe291a6ca33c20		 pdf-font-stream PDF embedded font (sfnt) at offset 0x7346 14240 bytes

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