Malicious PDF — malware analysis report

Static analysis result for SHA-256 d76c3f6f9a29e548…

MALICIOUS

PDF

79.4 KB Created: 2021-02-28 17:27:41 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: d14dae7f135a6660c3bcd8067d77ae9f SHA-1: 2130f1e35a14e979a8955125a6aa17311d9ba440 SHA-256: d76c3f6f9a29e5488e90348ed22622073754afa54f6e7629a56113113a54f63a
156 Risk Score

Malware Insights

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

The PDF contains a large number of external links, many of which are SEO-optimized and point to other PDF documents, suggesting a link farm or content stuffing tactic. One prominent URL, 'https://jacksth.ru/wix?keyword=barron%2527s+act+premium+study+guide', is presented as a study guide, likely a lure to direct users to a malicious site. ClamAV detection and ML classification strongly indicate malicious intent, consistent with phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

Heuristics 5

  • 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.
  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • External URI info PDF_URI
    PDF contains an external URL action
  • 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://jacksth.ru/wix?keyword=barron%2527s+act+premium+study+guide
    • https://cdn-cms.f-static.net/uploads/4471455/normal_6015b38204090.pdf
    • https://cdn-cms.f-static.net/uploads/4375885/normal_5fd6deb6d6f5b.pdf
    • https://cdn-cms.f-static.net/uploads/4368230/normal_600a52288026e.pdf
    • http://fuluwube.22web.org/free_chip_s_challenge_for_windows_7.pdf
    • http://wide-take.top/saneboxakasaxiwabonafuzo67xcn.pdf
    • https://cdn-cms.f-static.net/uploads/4473916/normal_60197559441aa.pdf
    • https://cdn-cms.f-static.net/uploads/4373997/normal_603065506110c.pdf
    • http://bit7.top/masayoshi_son_biographyb9y18.pdf
    • https://cdn-cms.f-static.net/uploads/4448984/normal_5fd0a8679f51f.pdf
    • http://ledimpress.biz/outsiders_final_projectwds8p.pdf
    • https://padilokemim.weebly.com/uploads/1/3/1/3/131381900/wosinunoje.pdf
    • https://static.s123-cdn-static.com/uploads/4486042/normal_6004ce2d7fbbe.pdf
    • https://cdn-cms.f-static.net/uploads/4451567/normal_60310a3846f82.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://s3.amazonaws.com/toliwudalamem/xebazikilipita.pdf
    • http://vuvixuvijoxozux.epizy.com/mendelian_corn_genetics_lab_report.pdf
    • http://zomefikike.rf.gd/27716963683.pdf
    • https://s3.amazonaws.com/safago/53_bank_open_saturday.pdf
    • https://s3.amazonaws.com/sefabe/66530219737.pdf
    • http://wavudipikudela.epizy.com/18277328411.pdf
    • https://s3.amazonaws.com/fevobelijogal/91413187025.pdf
    • http://mikesivu.rf.gd/vidutimomovapux.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_off0000f8d4.bin
ebd3bc9132dac7050a35bb14599c1833c776a03d2645119ae9c3dd5efd0910eb		 pdf-font-stream PDF embedded font (sfnt) at offset 0xF8D4 5548 bytes
font_01_sfnt_off00010bb5.bin
0930a1d33cf1603cd3ba5744a7e7aa29b032e4cdc3b2f2190ccfecc9dea983ae		 pdf-font-stream PDF embedded font (sfnt) at offset 0x10BB5 10500 bytes

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