Malicious PDF — malware analysis report

Static analysis result for SHA-256 4b1876bed8e558c1…

MALICIOUS

PDF

72.6 KB Created: 2021-05-24 07:41:33 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 18bdb8c9f5b4c4141cd31ab08516b5f5 SHA-1: 2571487597b1ed1545134337d08979ee8888f1a4 SHA-256: 4b1876bed8e558c1355a1ec8e7919e72c32fc978e0eda5cf27b7afc1ee5213b3
196 Risk Score

Malware Insights

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

The PDF file contains numerous external links, many pointing to S3 buckets, suggesting a link farm or SEO manipulation tactic. One prominent URL, 'https://resalured.ru/strik?utm_term=historias+de+amor+pdf+gratis', is flagged as suspicious and likely leads to a phishing or malware distribution site. The ML classifier and ClamAV detection strongly indicate malicious intent, and the 'SE_PASSWORD_ARCHIVE_LURE' heuristic suggests a common technique to bypass gateway security by encrypting a payload. No scripts were extracted, but the overall structure and URL patterns are consistent with phishing and malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 6

  • 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
  • Password-protected archive handoff high SE_PASSWORD_ARCHIVE_LURE
    Document gives password instructions for an archive or attachment — often used to keep payloads encrypted until after gateway scanning
  • 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://resalured.ru/strik?utm_term=historias+de+amor+pdf+gratis
    • https://lazumuron.weebly.com/uploads/1/3/4/8/134863931/kibez.pdf
    • https://puzaloraren.weebly.com/uploads/1/3/4/5/134510283/c1ab6c4e715081.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://s3.amazonaws.com/dozore/energy_storage_systems.pdf
    • https://s3.amazonaws.com/mokamoba/ejercicios_isotonicos.pdf
    • https://s3.amazonaws.com/wenobagupexekap/kuxeguf.pdf
    • https://s3.amazonaws.com/fefurorobumi/ribugizadufetute.pdf
    • https://s3.amazonaws.com/zumomasugipeno/fbise_date_sheet_2019_9th_class.pdf
    • https://s3.amazonaws.com/tobojelusiwi/dell_dimension_2350_drivers_windows_xp.pdf
    • https://uploads.strikinglycdn.com/files/3345448d-d3f7-4d2c-b71a-d96735e343fc/20505771883.pdf
    • https://s3.amazonaws.com/wowonesoribu/dejitibanevakov.pdf
    • https://s3.amazonaws.com/jemisajoda/54836715137.pdf
    • https://s3.amazonaws.com/nimuwet/badrinath_movie_tamil_dubbed_hd.pdf
    • https://s3.amazonaws.com/mejawiwomak/jirojetupi.pdf
    • https://s3.amazonaws.com/jotizifime/42262036843.pdf
    • https://s3.amazonaws.com/xalexojaxipud/worship_chord_progressions_piano.pdf
    • https://uploads.strikinglycdn.com/files/ab72b422-4e02-4ffd-9c6d-ff5dfbb21ef7/kinetico_premier_water_softener_price_uk.pdf
    • https://s3.amazonaws.com/wufujudisu/irrational_synonym_informal.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_off0000db60.bin
0e21da7ada25a12714191661ff4ba69f7f00cb1a4278c048d61c228c19cc0e62		 pdf-font-stream PDF embedded font (sfnt) at offset 0xDB60 5292 bytes
font_01_sfnt_off0000ed47.bin
34921a6c65a52fdd73701d4379aecec5baa1e00520ebb8625bbb11c2bf52be27		 pdf-font-stream PDF embedded font (sfnt) at offset 0xED47 11652 bytes

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