Malicious PDF — malware analysis report

Static analysis result for SHA-256 4a5cebe8c4ccc57a…

MALICIOUS

PDF

86.7 KB Created: 2021-03-28 05:25:12 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: db58386376d8f6ee43bb83ef9bf81c0d SHA-1: dbbb9c066833c2a62189239e1c48437555492214 SHA-256: 4a5cebe8c4ccc57a409a929495db42d5f153efe7c0df34ec415590dd246b93a2
156 Risk Score

Malware Insights

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

The PDF contains numerous external links, with a critical heuristic identifying it as a link farm designed to host multiple PDF files. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or malware distribution. The document body, though heavily obfuscated, contains metadata suggesting it was generated by wkhtmltopdf and references 'cooling tower performance calculation pdf', indicating a lure to attract users to malicious URLs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9992

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.
  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://jumiwimov.ru/award?keyword=cooling+tower+performance+calculation+pdf
    • http://fuwenosod.iblogger.org/zixuxidabem.pdf
    • https://cdn.sqhk.co/borefigux/EXjiaij/7054949390.pdf
    • https://rejasujewefem.weebly.com/uploads/1/3/0/7/130738882/bakoxurogoboxev-salotegobuvetid.pdf
    • https://jufasoxoko.weebly.com/uploads/1/3/5/3/135315704/8327419.pdf
    • https://cdn.sqhk.co/divoxisig/uhjqhP6/samurai_sword_training_adelaide.pdf
    • https://cdn.sqhk.co/dasupejej/E0dhaOM/25638025059.pdf
    • https://dinadexoliba.weebly.com/uploads/1/3/6/0/136091941/109191.pdf
    • https://negazebofukiwan.weebly.com/uploads/1/3/5/3/135318678/lesilex.pdf
    • http://jevufoduxixan.22web.org/69178885818.pdf
    • https://guserokofetaw.weebly.com/uploads/1/3/4/3/134341966/a9c2a0da.pdf
    • https://jimakujomeda.weebly.com/uploads/1/3/4/4/134438408/4b47dedc6b45.pdf
    • https://ramokazadi.weebly.com/uploads/1/3/4/4/134470245/c3209ac7f533d1d.pdf
    • https://pazovazorukilaz.weebly.com/uploads/1/3/4/6/134673506/880b62e03f592.pdf
    • https://wobanuwu.weebly.com/uploads/1/3/5/9/135959505/4653c6ef6dd5024.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • http://reluwiz.epizy.com/zivet.pdf
    • http://pakebojubo.rf.gd/46096160904.pdf
    • http://rerorisa.epizy.com/37398049170.pdf
    • http://nuvelerejide.rf.gd/how_to_start_collecting_contemporary_art.pdf
    • http://fizenigapajawak.epizy.com/jorovogalusut.pdf
    • http://jeragapa.epizy.com/aagadu_movie_comedy_scenes_free.pdf
    • http://lavaraf.epizy.com/decimal_into_percentage_worksheet.pdf
    • https://s3.amazonaws.com/saziwijaxodav/sheet_music_ashokan_farewell_violin_solo.pdf
    • https://s3.amazonaws.com/risisipajole/excellence_synonym_thesaurus.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_off00011158.bin
371c480c8cf991e96e3fa6b0027eb76f4e3dba9492b294e0f3a8ff33a31c486b		 pdf-font-stream PDF embedded font (sfnt) at offset 0x11158 5292 bytes
font_01_sfnt_off00012351.bin
0725a53203d222d7094316c1d11411c6d5c28cb48c095d387a89febfeef3d4fd		 pdf-font-stream PDF embedded font (sfnt) at offset 0x12351 11980 bytes

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