Malicious PDF — malware analysis report

Static analysis result for SHA-256 f5cc538dc6d690c5…

MALICIOUS

PDF

35.7 KB Created: 2020-05-19 08:46:35 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2020-08-25
MD5: 09145466d0755be8968befa1b1a62e45 SHA-1: 6b58e507b3c70c0cb873553b20c97e5f45e679c0 SHA-256: f5cc538dc6d690c56c1eda67d7c1693f51f2582fa17ee68846c3afb1324197a5
96 Risk Score

Malware Insights

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

The PDF file was identified as malicious by an ML classifier with high confidence. Static analysis revealed it functions as a link farm, containing numerous external URLs pointing to other PDF documents hosted across various domains. This suggests a tactic to manipulate search engine results or distribute further malicious content through a network of linked files.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9958

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://longbuilderscompany.com/uploads/1/3/0/3/130313366/130313366.html#kong+extreme+size+guide PDF link annotation
    • http://bodyrighttonic.com/uploads/1/3/0/7/130738859/xerakifimasi_bamuk_xolenitakij.pdfIn PDF document text
    • http://simrananand.com/uploads/1/3/0/8/130814411/114cdecdf56.pdfIn PDF document text
    • http://goldmedalsuccessconference.com/uploads/1/3/0/5/130588527/750662.pdfIn PDF document text
    • http://smt-metalltechnik.eu/uploads/1/3/1/4/131437725/genew.pdfIn PDF document text
    • http://pierredthomasgallery.com/uploads/1/3/0/5/130540397/kupileluseko_zesadegel.pdfIn PDF document text
    • http://spiceypepawear.com/uploads/1/3/0/3/130313319/ruzemiresimagagogopa.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn 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
    • http://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00005f1b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x5F1B 10416 bytes
SHA-256: 251bf9add8adf2c47a59710698c2a2585ff914f1624ed20f59acd6b96f334564