Malicious PDF — malware analysis report

Static analysis result for SHA-256 81664ed3918cc2fe…

MALICIOUS

PDF

46.8 KB Created: 2020-08-14 12:22:11 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 713c361868f3a83c44bf86056bef1129 SHA-1: c7182bcd54c72d0bc3465f922d79ef1e49e93753 SHA-256: 81664ed3918cc2fe1232dca8638f1915f1d63d23100ad64677de86562ed17207
154 Risk Score

Malware Insights

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

The PDF contains a large number of embedded links, many of which point to a redirector service. The document body, though heavily obfuscated, contains a URL that leads to a job interview questions page, likely a lure. The ML classifier and the redirector heuristic strongly indicate malicious intent, likely to redirect users to a phishing or malware distribution site.

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.cc/pify?keyword=job+interview+questions+for+freshers+with+answers
    • http://files.divinegemsvirtues.com/uploads/1/3/2/7/132740553/midopa.pdf
    • http://files.gnshs-pto.org/uploads/1/3/1/3/131398242/9955108.pdf
    • http://files.icaess.com/uploads/1/3/1/4/131483009/9200271.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://cdn.shopify.com/s/files/1/0431/0158/5570/files/pujadapo.pdf
    • https://cdn.shopify.com/s/files/1/0437/2224/4246/files/importance_of_creativity_and_innovation_in_entrepreneurship.pdf
    • https://cdn.shopify.com/s/files/1/0429/3342/0195/files/67320744359.pdf
    • https://cdn.shopify.com/s/files/1/0430/7802/5370/files/fegeriwalosodarewedovaloz.pdf
    • https://cdn.shopify.com/s/files/1/0433/0687/7080/files/34996744553.pdf
    • https://cdn.shopify.com/s/files/1/0435/3625/3087/files/career_goals_statement_examples.pdf
    • https://cdn.shopify.com/s/files/1/0433/0687/7080/files/93434530871.pdf
    • https://cdn.shopify.com/s/files/1/0429/9381/1619/files/79357605991.pdf
    • https://cdn.shopify.com/s/files/1/0434/3103/5047/files/beetroot_chutney_in_tamil.pdf
    • https://cdn.shopify.com/s/files/1/0437/9734/8514/files/patute.pdf
    • https://cdn.shopify.com/s/files/1/0430/6350/9141/files/gokosumowalolesuremi.pdf
    • https://cdn.shopify.com/s/files/1/0438/2218/6656/files/abscesso_hepatico_pediatria.pdf
    • https://cdn.shopify.com/s/files/1/0429/5219/6249/files/woful.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_off000079d3.bin
b06309196c950f26c98e7bbebc12147a7261c532d9d524a7bedc6dfa5c280f46
pdf-font-stream PDF embedded font (sfnt) at offset 0x79D3 5228 bytes
font_01_sfnt_off00008bac.bin
b28df3e5424f89f85a6e938fc9f24ca93657db40eb5ff68c1c7bbc9230c90bec
pdf-font-stream PDF embedded font (sfnt) at offset 0x8BAC 10080 bytes