Malicious PDF — malware analysis report

Static analysis result for SHA-256 31e0ec11dfcf449a…

MALICIOUS

PDF

50.7 KB Created: 2020-04-14 21:38:33 +03:00 Authoring application: wkhtmltopdf 0.12.1.4 (via Qt 4.8.6) First seen: 2020-12-25
MD5: 6e06a2ea3df7e1dbf5b548a03fd26e42 SHA-1: 9e9c52e29286476f65914a514834ea4630d12e4c SHA-256: 31e0ec11dfcf449a52e1ac85cdd68f86498b456360fe082e10a12737bf50692a
116 Risk Score

Malware Insights

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

The PDF file exhibits characteristics of malicious intent, including a malformed exploit stream and a high ML classifier score. It presents a lure of 'free piano sheet music' but contains a large number of external links, suggesting SEO manipulation or a link farm for distributing further malicious content. The presence of embedded URLs and the PDF_SEO_LINK_FARM heuristic indicate a coordinated effort to distribute malicious PDFs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9955

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.
  • Malformed active-content stream length medium PDF_MALFORMED_EXPLOIT_STREAM_LENGTH
    A PDF stream that carries active/exploit-looking content has a declared /Length that does not match the recovered stream body. Malformed stream boundaries and length mismatches are common parser-evasion/supporting evidence around Reader exploit streams.
  • 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://shreejicleaningservices.com/uploads/1/3/0/7/130740138/130740138.html#free+piano+sheet+music+blank PDF link annotation
    • http://plussizeweddingdressesma.com/uploads/1/3/0/3/130323566/pinoxufuzimosinapap.pdfIn PDF document text
    • http://desotomethodistchurch.com/uploads/1/3/0/5/130590059/658bec3106492.pdfIn PDF document text
    • http://grahams-gallery.com/uploads/1/3/0/6/130639518/9821431.pdfIn PDF document text
    • http://exclusivecarenursing.com/uploads/1/3/0/2/130291492/begeludin-rafegufupa-gifuxiboweporel.pdfIn PDF document text
    • http://riverfront-residences-hougang.com/uploads/1/3/1/4/131453230/6711045.pdfIn PDF document text
    • http://tattoosoritdidnthappen.com/uploads/1/3/1/3/131380388/vuzufutefabuton_nadadole_xuligaro_fumupux.pdfIn PDF document text
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00009e21.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x9E21 8304 bytes
SHA-256: 08134377e91e5abf4b9fe4a6f4b357516dec2e0e55499c83455a5b82fa14a6af

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