Malicious PDF — malware analysis report

Static analysis result for SHA-256 c16821dc6441f5df…

MALICIOUS

PDF

42.3 KB Created: 2020-07-09 09:19:05 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2020-09-04
MD5: 18e9efc1d39df532093a6fd7bd4b0383 SHA-1: 4ce0608af8c355e1c9374fee226c3cd5dd082608 SHA-256: c16821dc6441f5df87ef76d9eaa80623f4269306895dae6b71b95ff7232b895a
184 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1204.001 Malicious Link T1059.001 PowerShell

The PDF contains a large number of embedded links, many of which point to domains associated with link farms and redirectors, as indicated by the PDF_SEO_LINK_FARM and PDF_MALICIOUS_REDIRECTOR_LINK heuristics. The ML classifier also strongly flagged this PDF as malicious. The document body, while containing garbled text, includes the phrase 'Variables in an experiment worksheet answers' and the URL https://ttraff.cc/wb?keyword=variables%20in%20an%20experiment%20worksheet%20answers, suggesting a lure to a potentially malicious resource disguised as educational content.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 5

  • 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.
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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/wb?keyword=variables%20in%20an%20experiment%20worksheet%20answers In PDF document text
    • http://files.zportman.com/uploads/1/3/0/8/130814735/8c7cece.pdfIn PDF document text
    • http://files.leafingthroughbooksandtea.com/uploads/1/3/1/6/131606854/7711173.pdfIn PDF document text
    • http://files.strongcap.com/uploads/1/3/0/7/130776249/towugi-jonez-giwewanepurimop.pdfIn PDF document text
    • http://files.cai-ohio.com/uploads/1/3/0/9/130969607/3caa640217eb5.pdfIn PDF document text
    • http://files.centrepointecincinnati.com/uploads/1/3/1/4/131406413/e08b8.pdfIn PDF document text
    • http://files.menefeehamps.com/uploads/1/3/0/8/130814535/xewawuse.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://panamekeze.files.wordpress.com/2020/06/10122616087.pdfIn PDF document text
    • https://kikibok.files.wordpress.com/2020/06/jitazilupisegalujijedapet.pdfIn PDF document text
    • https://fusikazisome.files.wordpress.com/2020/07/87914616626.pdfIn PDF document text
    • https://fakoxej.files.wordpress.com/2020/07/23512689537.pdfIn PDF document text
    • https://zikokiso.files.wordpress.com/2020/07/xukibujewakarurewusomexep.pdfIn PDF document text
    • https://fakenigali.files.wordpress.com/2020/06/xabesudunaz.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0428/9835/8432/files/64989875230.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0428/9835/8432/files/fatexuxutul.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0428/9835/8432/files/mojarugalemidim.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0428/9835/8432/files/58014629257.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0428/9835/8432/files/zemeletitofugawekabol.pdfIn PDF document text
    • https://cdn.shopify.com/s/files/1/0428/9835/8432/files/84312174386.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
    • http://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000673f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x673F 5176 bytes
SHA-256: ff23d09190450d263431fcb83d309ddc9cdd20167c21f4212b1e9ee87b5c4a78
font_01_sfnt_off000078af.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x78AF 10384 bytes
SHA-256: f8cf2c03244075ee8ef817387216edd5eb477c4e4c3fc16af606680046db03ea