Malicious PDF — malware analysis report

Static analysis result for SHA-256 dc37d540bd5c3187…

MALICIOUS

PDF

70.4 KB Created: 2021-02-15 11:46:36 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-22
MD5: 200ca378562306921f8029300781cd4b SHA-1: d2f0b8c3b352285a59df7a448b8f81645d380aa9 SHA-256: dc37d540bd5c3187798a86f6c051a9e772350017c023c4dac25e864b45b2ded1
126 Risk Score

Malware Insights

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

The PDF document contains a large number of external links, many of which point to disposable hosting and appear to be part of a link farm. The document body, though heavily obfuscated, suggests a lure related to educational content. The ML classifier strongly indicates maliciousness, and the presence of numerous external URIs suggests an attempt to redirect users to potentially harmful sites, possibly for SEO spam or phishing.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • 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://leonvi.ru/strik?utm_term=volume+of+a+rectangular+prism+worksheet+5th+grade PDF link annotation
    • http://vashmaster.info/misepudawodukagebefukeflfoo.pdfIn PDF document text
    • https://cdn.sqhk.co/letaziseb/ajdjagh/fokerukitozujexer.pdfIn PDF document text
    • https://julubagarod.weebly.com/uploads/1/3/2/6/132695517/2554372.pdfIn PDF document text
    • https://cdn.sqhk.co/pasepizut/fieoxnv/mawipubuli.pdfIn PDF document text
    • http://devlp.design/sentence_using_conjunctive_adverbsl95sb.pdfIn PDF document text
    • https://cdn.sqhk.co/sodelaranu/CjeQRVz/hot_videos_not_on_youtube_2019.pdfIn PDF document text
    • https://sogatetemurus.weebly.com/uploads/1/3/4/3/134379625/vuloniz.pdfIn PDF document text
    • https://cdn.sqhk.co/wapiwogemi/fgeggse/merriam_webster_dictionary_download.pdfIn PDF document text
    • http://7lessons.site/masipawozizobizcmmhq.pdfIn PDF document text
    • https://cdn.sqhk.co/bulunazi/iigcgiJ/bokogor.pdfIn PDF document text
    • https://cdn.sqhk.co/guwuweri/dYjjiih/ding_dong_deli_nj.pdfIn PDF document text
    • http://mobevusujezuno.22web.org/fovorarorudesudekofu.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/nademopor/shri_hanuman_amritwani_part_2_song.pdfIn PDF document text
    • http://mapojadesagez.epizy.com/sefikibusakabuv.pdfIn PDF document text
    • http://nivewurunowu.rf.gd/railroad_tycoon_1_manual.pdfIn PDF document text
    • https://s3.amazonaws.com/gurupixabogivaz/25926492801.pdfIn PDF document text
    • http://wuwatomugexove.epizy.com/vujiwelowokunezuriganewa.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_off0000d4f1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD4F1 5816 bytes
SHA-256: b838893c5901574f71b27ca8326677ebc9d026c62feb10c575f8b99ee3e235f3
font_01_sfnt_off0000e8b1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE8B1 10436 bytes
SHA-256: 90450fe4464b0686a975f28edec8dfbed79429c900e48d72cf83862ccaa21cfb

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