Malicious PDF — malware analysis report

Static analysis result for SHA-256 b81fc80b707ccd68…

MALICIOUS

PDF

64.7 KB Created: 2021-02-24 11:32:29 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-22
MD5: 1b9d188a8879068a28c7503c59d55dcf SHA-1: 41af9fc42a434be56136e5ad6800e7be6fa8af41 SHA-256: b81fc80b707ccd68b9f2ccd7309f650d18d87f2765688275c3ef492ac1c6dbe7
156 Risk Score

Malware Insights

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

The sample is a PDF file detected as malicious by ClamAV and an ML classifier. It contains a large number of external links, many pointing to PDF files on various domains, suggesting a link farm or redirection mechanism. The document body is heavily obfuscated, but the presence of external URIs and the PDF_SEO_LINK_FARM heuristic indicate an attempt to direct users to potentially malicious content. No scripts were extracted, but the nature of the links suggests a phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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 https://baarspo.ru/aws?utm_term=capitalization+and+punctuation+worksheets+2nd+grade+pdf PDF link annotation
    • https://nozagovedenide.weebly.com/uploads/1/3/2/6/132682533/7942967.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4415327/normal_60320b8d8ecd6.pdfIn PDF document text
    • https://lefiluke.weebly.com/uploads/1/3/4/8/134887161/8778225.pdfIn PDF document text
    • http://astrohelp.space/tokexomerubozifekuyeog4.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4449990/normal_60142713dded5.pdfIn PDF document text
    • http://edaruzal.xyz/pexidegidev8s94c.pdfIn PDF document text
    • http://top-agent.ru/excel_drop_down_list_to_filter_worksheethnngt.pdfIn PDF document text
    • http://bokugezus.66ghz.com/puxisiguvikasaromonewe.pdfIn PDF document text
    • http://mamimufexaliro.66ghz.com/66568568895.pdfIn PDF document text
    • https://dudegakabiwuzab.weebly.com/uploads/1/3/1/4/131406663/zewivibonog.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4406782/normal_6017348e0aac5.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4403946/normal_6007ea0e35ef8.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://s3.amazonaws.com/fasomusogapovi/64357900612.pdfIn PDF document text
    • https://s3.amazonaws.com/woxorojero/how_to_get_stock_symbol_list.pdfIn PDF document text
    • https://s3.amazonaws.com/pafiganovavi/97870583592.pdfIn PDF document text
    • https://s3.amazonaws.com/somisilegex/miromimuloduguxefov.pdfIn PDF document text
    • http://zapuvem.epizy.com/xixidegabimijejufigulek.pdfIn PDF document text
    • https://s3.amazonaws.com/zarevizebi/44345344850.pdfIn PDF document text
    • https://s3.amazonaws.com/bizamesuwepe/article_html5_template.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_off0000bebb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBEBB 5660 bytes
SHA-256: e529ff0bc7cab5fde4bc24021cff651e52bbbe0b138dcdcdd63401b844202df0
font_01_sfnt_off0000d217.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD217 10400 bytes
SHA-256: 8ba92750d48e9a4c34f1f5c10c605240513d114e701749fed1aed44e3b08f148

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