Malicious PDF — malware analysis report

Static analysis result for SHA-256 8c335022c2cbf634…

MALICIOUS

PDF

37.7 KB Created: 2020-08-04 14:49:00 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: cb37d999deccb68a42238a85e0b7a389 SHA-1: 6b92311f5f9961afa2ced23c7f774a74fdfaae84 SHA-256: 8c335022c2cbf634ab55743092cc2b67c070469837b5796bd70dcbce9a1cc50c
152 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains a mass of external links, many pointing to Shopify domains hosting other PDFs, and one critical link to a known malicious redirector. The document body, though heavily obfuscated, contains text related to 'skeletal system worksheets for grade 4' and the malicious URL, suggesting a lure to trick users into clicking the malicious link. The ML classifier strongly indicated maliciousness.

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/wb?keyword=skeletal%20system%20worksheets%20for%20grade%204
    • http://files.genehamiltonartist.com/uploads/1/3/1/8/131871704/7686114.pdf
    • http://files.transcend-ed.com/uploads/1/3/0/9/130968926/turir-dekabojov-jexiv-rexajuxe.pdf
    • http://files.contigodevelopment.com/uploads/1/3/2/3/132303219/resowewaxaronivipid.pdf
    • http://files.evedevon.com/uploads/1/3/0/7/130740432/xetevezokubozok.pdf
    • https://cdn.shopify.com/s/files/1/0431/1931/3053/files/telojaruzerikezufavuxiri.pdf
    • https://cdn.shopify.com/s/files/1/0433/9384/3358/files/womajetuti.pdf
    • https://cdn.shopify.com/s/files/1/0428/0185/6679/files/84780983247.pdf
    • https://cdn.shopify.com/s/files/1/0432/6745/7188/files/bojoditomix.pdf
    • https://cdn.shopify.com/s/files/1/0430/7946/7170/files/27582253281.pdf
    • https://cdn.shopify.com/s/files/1/0431/7318/3643/files/98739576009.pdf
    • https://cdn.shopify.com/s/files/1/0435/2914/2426/files/37521866751.pdf
    • https://cdn.shopify.com/s/files/1/0430/7556/7777/files/57348342821.pdf
    • https://cdn.shopify.com/s/files/1/0432/1404/5341/files/kakagikufogojoguxodufuzoj.pdf
    • https://cdn.shopify.com/s/files/1/0431/2042/7157/files/rijamijik.pdf
    • https://cdn.shopify.com/s/files/1/0429/0487/9271/files/piwuwako.pdf
    • https://cdn.shopify.com/s/files/1/0430/3349/3655/files/84826023824.pdf
    • https://cdn.shopify.com/s/files/1/0427/6033/9623/files/28403683955.pdf
    • https://cdn.shopify.com/s/files/1/0434/4319/1969/files/46038871041.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/

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00005318.bin
2d5c0001cc08bafe35cdd948b18665e1b6c0388436ebfaf6c26f60daf94e5476		 pdf-font-stream PDF embedded font (sfnt) at offset 0x5318 5768 bytes
font_01_sfnt_off000066b2.bin
f80be80bef3dbc2777c5f8eafb32878854c57ddd7bd3333da80e3db4f01b4b3c		 pdf-font-stream PDF embedded font (sfnt) at offset 0x66B2 10224 bytes

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