Malicious PDF — malware analysis report

Static analysis result for SHA-256 3c5f08883ca248fd…

MALICIOUS

PDF

43.3 KB Created: 2020-05-15 00:08:03 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 34f01405bd7a714896369c4f61602480 SHA-1: bece72b4400fcbce0a3bd82590874d9596180c7a SHA-256: 3c5f08883ca248fdfe69809675ab65eb549a4986b4bbf202f596a099d51f25e8
94 Risk Score

Malware Insights

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

The PDF contains a large number of external links, many of which point to suspicious domains, indicating a link farm or SEO poisoning tactic. The ML classifier also strongly flagged this PDF as malicious. The document body, though partially corrupted, contains references to 'Skype for business server 2015 enterprise' and 'wkhtmltopdf', suggesting a potential lure or disguise. The primary attack pattern involves directing users to these external URLs, which likely host further malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9887

Heuristics 4

  • 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.
  • 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 http://minnesotahydrographics.com/uploads/1/3/0/6/130639407/130639407.html#skype+for+business+server+2015+enterprise
    • http://20180509.xyz/uploads/1/3/0/6/130621325/fe3bd725.pdf
    • http://acdangheating.net/uploads/1/3/0/4/130436204/2530768.pdf
    • http://yunnanfashion.com/uploads/1/3/0/2/130289448/sorilevaveg.pdf
    • http://stillonthetrail.com/uploads/1/3/0/6/130621030/gunubekafusoru.pdf
    • http://100leaderswhocook.com/uploads/1/3/0/3/130323249/9611861.pdf
    • http://reconstructivewellness.com/uploads/1/3/0/4/130435821/pivazeneximuko_puwozagadavexu_konigiw_banidamixaw.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 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00007dd4.bin
1322c2829bc80eea07c92f48c7ffeaf5b726a3ff32b47511e02c7af59be23211		 pdf-font-stream PDF embedded font (sfnt) at offset 0x7DD4 10700 bytes

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