Malicious PDF — malware analysis report

Static analysis result for SHA-256 81f933624a4b5d8f…

MALICIOUS

PDF

82.3 KB Created: 2021-09-20 16:57:47 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: e043fc15273d75513d21001b85e54cc6 SHA-1: 935dd0b8688c80dfeaa7f5fe38efdeb56350859d SHA-256: 81f933624a4b5d8f724008aafb8d6c03112e5312af63bd5142479702c52b9979
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by ML classifiers and ClamAV as malicious, indicating a high likelihood of malicious intent. The heuristic analysis revealed a large number of embedded external URIs, many of which are hosted on disposable domains, suggesting a link farm or phishing lure. Although no scripts were explicitly extracted, the PDF structure and embedded links are consistent with techniques used to redirect users to malicious sites for further exploitation.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

Heuristics 5

  • 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.
  • 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://transport.frontiermyanmar.com/sites/all/libraries/ckfinder/userfiles/files/mazanajagivodedadozorudo.pdf In PDF document text
    • http://pokebarslo.com/uploads/files/46704871026.pdfIn PDF document text
    • https://fallsplat.se/bildbank/file/6643885450.pdfIn PDF document text
    • http://www.siscard.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613476c54f406---kujubisuroj.pdfIn PDF document text
    • http://vers-ma.de/userfiles/file/nogironoxigozikizigidimi.pdfIn PDF document text
    • https://asesoriagade.com/app/webroot/files/files/tufed.pdfIn PDF document text
    • http://agriturismolionsfarm.it/userfiles/files/barekagojebimepuruvufo.pdfIn PDF document text
    • http://cnwt.mgo.cool/upfile/files/2021/09/18/direpuxozufagozo.pdfIn PDF document text
    • https://www.mmgrowersg.com/ckfinder/userfiles/files/rekowiwosowozimu.pdfIn PDF document text
    • https://petribax.nl/userfiles/file/59107211565.pdfIn PDF document text
    • http://yuhao-tech.com/userfiles/file/getejom.pdfIn PDF document text
    • http://rent2day.ca/ci2/userfiles/files/68371181456.pdfIn PDF document text
    • http://sskj.pl/userfiles/file/zasuzutadizujodelivini.pdfIn PDF document text
    • https://mkycc4.com/kycc4.com/userfiles/files/tovipelixasebapexino.pdfIn PDF document text
    • http://nobody-films.com/bpms/includes/fckeditor_uploads/userfiles/file/zupevivugovarif.pdfIn PDF document text
    • https://angkortaxiservice.com/userfiles/file/zeselesa.pdfIn PDF document text
    • https://lyna-garage.com/htdocs/cljr/data/files/10756570192.pdfIn PDF document text
    • http://www.taylormadetc.com/siteadmin/ckfinder/userfiles/files/73740448527.pdfIn PDF document text
    • https://dnmpaint.com/sdcc/images/file/kawesumodozamope.pdfIn PDF document text
    • https://rarahil.org.np/ckfinder/userfiles/files/32262082213.pdfIn PDF document text
    • http://avtokapriz42.ru/userfiles/file/rinawuwovisilalewuvebo.pdfIn PDF document text
    • https://jaukiaplinka.lt/ckfinder/userfiles/files/36598064793.pdfIn PDF document text
    • https://anna-bel.com/app/webroot/files/userfiles/files/35208509188.pdfIn PDF document text
    • http://yuanhebiotech.com/upload/files/fadogepar.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/3CAf4wW3hvY/uplcv?utm_term=instagram+followers+mod+apk+appPDF link annotation
    • http://e1pl2.nazwa.pl/busy/fotki/file/54358298042.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://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000dd99.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDD99 17192 bytes
SHA-256: 4eb4401d07c4deb9c7b8f65d17168c99d5845705ffd41ec855c9bc2d47891706
font_01_sfnt_off00010a0d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10A0D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012224.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12224 10880 bytes
SHA-256: bd98abb3595bcb1eb2766638ce6a4e5b18659e28e198be3d41cf28cb302e59cd