Malicious PDF — malware analysis report

Static analysis result for SHA-256 cf87e471c461db48…

MALICIOUS

PDF

76.1 KB Created: 2021-02-20 07:43:12 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-21
MD5: 52f244311e7c9dd309e96d659a39172e SHA-1: 203707a2236b1ca57af607f230a44765ffca5161 SHA-256: cf87e471c461db488bcb3b8cf0f76f78f9d573e2c1abb4ceb428b851f41ff641
244 Risk Score

Malware Insights

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

The file is a PDF containing a significant number of embedded URLs, many of which are part of a link farm hosted on disposable domains or known malicious redirectors. The ClamAV detection and ML classifier strongly indicate malicious intent, likely for phishing or distributing further malware. While no scripts were explicitly extracted, the PDF structure and embedded links are indicative of a malicious document designed to lure users to external, potentially harmful, sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://yafferge.ru/123?utm_term=apollo+twin+mk2+duo+vs+quad In PDF document text
    • https://gefobivuvevu.weebly.com/uploads/1/3/1/3/131380717/8932632.pdfIn PDF document text
    • https://cdn.sqhk.co/ragejeli/Xb0icjg/53239430441.pdfIn PDF document text
    • https://cdn.sqhk.co/velijituma/higjaGY/44998391621.pdfIn PDF document text
    • https://cdn.sqhk.co/sobexofap/Fogiijq/75722358067.pdfIn PDF document text
    • https://cdn.sqhk.co/gukisafuw/GijOibg/19549737809.pdfIn PDF document text
    • https://lipamonevarila.weebly.com/uploads/1/3/1/4/131453989/giripipanopa.pdfIn PDF document text
    • https://cdn.sqhk.co/gefimiwotux/aMhgjgW/rise_up_andra_day_piano_sheet_music_free.pdfIn PDF document text
    • http://xoxinusenavi.66ghz.com/mathemagic_6_answer_book_online.pdfIn PDF document text
    • https://cdn.sqhk.co/xubulozirod/igLp88r/19668598764.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://jutivowewinuled.epizy.com/luxuxowomuniga.pdfIn PDF document text
    • http://bupomejov.epizy.com/wazeg.pdfIn PDF document text
    • https://s3.amazonaws.com/falufusu/61858832796.pdfIn PDF document text
    • http://kujujigufa.epizy.com/adblock_for_chrome_android_tablet.pdfIn PDF document text
    • http://kimisudo.rf.gd/56742962564.pdfIn PDF document text
    • https://s3.amazonaws.com/tetofamuxulil/79402240835.pdfIn PDF document text
    • http://besikinugid.epizy.com/61969506963.pdfIn PDF document text
    • http://xamufalifab.epizy.com/choir_application_letter_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_off0000eb61.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEB61 5472 bytes
SHA-256: 9903d60482939b58e37772cdc0e22768bf88a56614abb1c15fd44b713904c7af
font_01_sfnt_off0000fe05.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFE05 11088 bytes
SHA-256: 0d3e6fc47d767e71835c9e99fffb542cbca90f8e49a39982c86d63416593c85f

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