Malicious PDF — malware analysis report

Static analysis result for SHA-256 b46a52f6555823e0…

MALICIOUS

PDF

78.4 KB Created: 2021-04-23 02:11:30 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 87f4d5fd340a66f636deeda76ed20dd4 SHA-1: b74092dd27d99b87e67264dd60f18db9b6550f48 SHA-256: b46a52f6555823e078697701666e610cec6f610b0c98d1bb0bb2ae698a290283
184 Risk Score

Malware Insights

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

This PDF file was flagged as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. It contains numerous embedded URLs, with at least one pointing to known malicious redirector infrastructure (https://yafferge.ru/strik). The document body, though heavily obfuscated, appears to contain metadata related to 'Optiplex 780 ram' and 'wkhtmltopdf', suggesting a potential lure or disguise. The presence of multiple links on disposable hosting further supports a phishing or malware distribution scheme.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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.
  • 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 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/strik?utm_term=optiplex+780+ram
    • http://mebevevi.mywebcommunity.org/jogakizukosavalozotijowa.pdf
    • https://cdn-cms.f-static.net/uploads/4443821/normal_601d31fa4c97e.pdf
    • http://fejazeluxuz.22web.org/ben_10_alien_ultimate.pdf
    • https://cdn-cms.f-static.net/uploads/4366376/normal_5fd28b7f2c74d.pdf
    • https://cdn-cms.f-static.net/uploads/4482188/normal_5fdbe6c6c1e98.pdf
    • https://cdn-cms.f-static.net/uploads/4484632/normal_60202d792a263.pdf
    • http://sakulog.sportsontheweb.net/paradoxo_do_aniversrio.pdf
    • http://gejokakop.mygamesonline.org/brain_teasers_worksheets_for_adults.pdf
    • https://cdn-cms.f-static.net/uploads/4380226/normal_602fd1ee95244.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • http://gozudil.onlinewebshop.net/60087463840.pdf
    • http://wonenuw.epizy.com/tebaxen.pdf
    • http://torejejowomu.myartsonline.com/calligramme_apollinaire.pdf
    • http://pogetowem.onlinewebshop.net/rejajarokojabugozibaf.pdf
    • https://9f9bd9fa-00fe-4673-b34e-9a629881f524.filesusr.com/ugd/09273f_344ce44a38304f0abc1dc276b82ca54b.pdf?index=true
    • http://powagamojij.onlinewebshop.net/15369740124.pdf
    • http://pusapovewazigu.onlinewebshop.net/simple_sentence_of_word_weekends.pdf
    • https://43fe4710-460a-4ad3-90dc-2dd795c51528.filesusr.com/ugd/a32c20_ef3fc1644a8747e7944eb7281301c8ef.pdf?index=true
    • https://b7d3a0ae-8059-487b-8826-088776693174.filesusr.com/ugd/8d23e4_3db180a4fb88472495fd2c3603df4de3.pdf?index=true
    • http://keregimuw.onlinewebshop.net/best_stock_broker_for_beginners_in_india_2020.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://scripts.sil.org/OFL

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f3e0.bin
86611cc3d384a7aeaa77fbc0c2a814c3c17f8475fe83e3e1cebe7ad2260352dc		 pdf-font-stream PDF embedded font (sfnt) at offset 0xF3E0 5296 bytes
font_01_sfnt_off000105de.bin
e178dd95583a9772bdf4ac98c23778f937d85a48d39710e89470b1c5156a5640		 pdf-font-stream PDF embedded font (sfnt) at offset 0x105DE 11584 bytes

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