Malicious PDF — malware analysis report

Static analysis result for SHA-256 b800b9f7535e7a25…

MALICIOUS

PDF

81.0 KB Created: 2021-02-24 07:42:07 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-20
MD5: 1c653f86b091a30523efd1df94c744d8 SHA-1: 8f76cdd6e209d8609122cb43c0d913655759775c SHA-256: b800b9f7535e7a253a780186381ef0d3ac4fbcabf3e2ea0c5d9f7cce5179ddff
186 Risk Score

Malware Insights

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

The PDF document contains a mass of external links, many hosted on disposable domains, designed to appear as SEO content. The primary malicious URL, 'https://baarspo.ru/strik?utm_term=clases+de+guitarra+clasica+online+gratis', is presented as a lure for free online guitar lessons, but the heuristic firings and ML classifier strongly indicate it is a phishing or malware distribution attempt. No scripts were extracted, but the PDF structure and link farm behavior are indicative of malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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.
  • 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.
  • 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/strik?utm_term=clases+de+guitarra+clasica+online+gratis PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4421629/normal_6019ae6c583e3.pdfIn PDF document text
    • https://kutemipemowu.weebly.com/uploads/1/3/4/8/134860595/xibefazebi-wodulizimixot-povaxugeju.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4448124/normal_5fd135e1d3f2e.pdfIn PDF document text
    • https://xuvosaxefon.weebly.com/uploads/1/3/4/6/134605895/wesagugu.pdfIn PDF document text
    • http://xsafak.com/flannel_sheets_king_single4ya4c.pdfIn PDF document text
    • https://febumade.weebly.com/uploads/1/3/4/7/134757335/4236117.pdfIn PDF document text
    • https://sefaxamijewosaw.weebly.com/uploads/1/3/2/6/132682716/e78c7d783cc8616.pdfIn PDF document text
    • https://duparumiwope.weebly.com/uploads/1/3/4/7/134707207/1009653.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4388283/normal_60259e7621bb9.pdfIn PDF document text
    • https://zefisazivite.weebly.com/uploads/1/3/5/3/135314851/sudekimoguv.pdfIn PDF document text
    • http://apparently-home.com/87961047157mowvw.pdfIn PDF document text
    • http://apple-fruit.space/android_bitmap_recycle_necessaryw7rt6.pdfIn PDF document text
    • https://torovuzexas.weebly.com/uploads/1/3/2/7/132710592/22420460c725c.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://tekaxebabix.epizy.com/kitetivax.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
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000de03.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDE03 5012 bytes
SHA-256: f7a7f6919aa2a034a15b184c63ba3514eb9e5e495f705b4bb078db7f103be75d
font_01_sfnt_off0000ef12.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEF12 1800 bytes
SHA-256: 51ebeec29509b87aa858d500e37ac8853184703d07d1f913ce36d8e1dc7764c0
font_02_sfnt_off0000f7a0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF7A0 12216 bytes
SHA-256: d3b1b6f0d37bc7c66ec09901467b71a1bd6effc7658f8e569f1369304b885c1c
font_03_sfnt_off00011ef8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11EF8 16312 bytes
SHA-256: bf8f9ece8d9d74ce2d7a98a07ee1bb8f4056faf702b3b1702118181e85f1b939

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