Malicious PDF — malware analysis report

Static analysis result for SHA-256 7dc4e09b45a94d87…

MALICIOUS

PDF

48.2 KB Created: 2020-08-31 12:43:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 9500536a9fdb5cd0c22f380a072a44cc SHA-1: 3d25ec6bc2eb7099fe4ad15ce060e6ac7775084a SHA-256: 7dc4e09b45a94d8727b43cf8c73527f416b0fe4be4baf24d179992568d9834a8
154 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains a heuristic firing for linking to known malicious redirector infrastructure, specifically a URL designed to look like a search result for an academic PDF. This URL, https://ttraff.ru/wix?keyword=college+accounting+13th+edition+pdf, is the primary IOC. The document also contains a large number of external PDF links, suggesting a link farm, with the first URL being https://static.usrfiles.com/ugd/b8c837_da5cbadefd1b449c8b1031826a4d9e80.pdf. The ML classifier strongly flagged this PDF as malicious.

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.ru/wix?keyword=college+accounting+13th+edition+pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://static.usrfiles.com/ugd/b8c837_da5cbadefd1b449c8b1031826a4d9e80.pdf
    • https://static.usrfiles.com/ugd/39cb9d_0a785f2b0aa54740aa9200ed902761d0.pdf
    • https://static.usrfiles.com/ugd/79e0dc_4b17848d49904069b037c192a933c656.pdf
    • https://static.usrfiles.com/ugd/ac72e0_af2ec2acb75e409d80baeca712651b61.pdf
    • https://cdn.shopify.com/s/files/1/0429/7791/9129/files/lagebedusajujuk.pdf
    • https://cdn.shopify.com/s/files/1/0432/6372/1637/files/95727106644.pdf
    • https://cdn.shopify.com/s/files/1/0436/1755/0499/files/letter_of_reference_templates_free.pdf
    • https://cdn.shopify.com/s/files/1/0434/6983/2342/files/nintendo_ds_emulator_apk.pdf
    • https://cdn.shopify.com/s/files/1/0432/9455/6324/files/nafemexe.pdf
    • https://cdn.shopify.com/s/files/1/0430/2834/9085/files/87534220289.pdf
    • https://cdn.shopify.com/s/files/1/0448/3337/4369/files/sikumaposubarefefe.pdf
    • https://cdn.shopify.com/s/files/1/0434/1796/0604/files/mukixifax.pdf
    • https://cdn.shopify.com/s/files/1/0436/2915/0368/files/lokegufirefilovidepulaj.pdf
    • https://static.usrfiles.com/ugd/b8c837_e7dec993685842a59996048e02d31b77.pdf
    • https://static.usrfiles.com/ugd/b8c837_c4a474de23234ad19ff6efe174bdf19a.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_off00007cdc.bin
fb264ee870bd52b8444deb9455aed651a56985d025f19ca3232145c4a6b1ec8a		 pdf-font-stream PDF embedded font (sfnt) at offset 0x7CDC 5264 bytes
font_01_sfnt_off00008ecd.bin
4cdd123b70ff2dbe8c8fee0e1b9d34bfc20720dedc302ad9ab507e562b13fa58		 pdf-font-stream PDF embedded font (sfnt) at offset 0x8ECD 10892 bytes

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