Malicious PDF — malware analysis report

Static analysis result for SHA-256 781fd8a630a76e02…

MALICIOUS

PDF

99.0 KB Created: 2021-09-15 20:30:22 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: a950a6bbceffcfdcbf50e41bcc4a51b1 SHA-1: 29a797720116dfbdb67467f39fe5ea16bb9ee1ee SHA-256: 781fd8a630a76e020bf8a96988d1f8f813d363e488de0bd4a12084d46a53a495
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is identified as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. The PDF contains numerous embedded URLs, with one specifically pointing to a suspicious domain ('synerhu.ru') and a query parameter suggesting a lure for 'equalizer software'. This pattern is consistent with phishing or malware distribution, where users are tricked into visiting malicious sites. No scripts were extracted, but the PDF structure and embedded URIs strongly suggest a malicious intent to redirect users.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9961

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://synerhu.ru/uplcv?utm_term=equalizer+software+for+android PDF link annotation
    • https://adetexfoamgroup.centralcms.cloud/galeria/files/kokusosonezo.pdfIn PDF document text
    • https://renetravel.ro/images/files/zevomixijukovuma.pdfIn PDF document text
    • http://chongthamnguoc.vn/img/files/poxasofelalixudunejirofe.pdfIn PDF document text
    • https://hophamthaibinh.com/upload/files/filububivuguxopuliga.pdfIn PDF document text
    • http://mebelhotel.ru/images/news/file/2012125643.pdfIn PDF document text
    • http://inistor.com/ufiles/files/60162679588.pdfIn PDF document text
    • http://www.frank-diagn.hu/userfiles/files/99875854660.pdfIn PDF document text
    • https://highrise.pl/file/giduvuwumajuwak.pdfIn PDF document text
    • http://energosol.pl/images_cms/file/22691121461.pdfIn PDF document text
    • http://nomayaku.com/userfiles/file/xowewul.pdfIn PDF document text
    • http://rayer.cn/d/files/52613634848.pdfIn PDF document text
    • https://a2designbg.com/userfiles/file/24317149444.pdfIn PDF document text
    • http://kapsalonindex.nl/images/uploads/5567264198.pdfIn PDF document text
    • https://hmanagement.net/userfiles/file/74737299064.pdfIn PDF document text
    • http://quiltingacademy.com/fckeditor/userfiles/file/34779912356.pdfIn PDF document text
    • http://akgwealthplanner.com/crm/files/55902555229.pdfIn PDF document text
    • http://htwy.com/upload/file/6845138358.pdfIn PDF document text
    • http://steinemann-ag.ru/resozajofuxadezov.pdfIn PDF document text
    • https://www.pessin-location.fr/ckfinder/userfiles/files/ginow.pdfIn PDF document text
    • http://remontnoedelo.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1613cab2b33fd0---biropiwo.pdfIn PDF document text
    • http://retco.ge/ckfinder/userfiles/files/zimomazutegeboniluzaxonal.pdfIn PDF document text
    • http://kuhomania.ru/ckfinder/userfiles/files/39857067866.pdfIn PDF document text
    • http://xindeshiye.com/uploadfile/file///2021091400025124.pdfIn PDF document text
    • http://naturalwonders.com/uploads/files/45193651723.pdfIn PDF document text
    • http://dakmoto.cz/obrazky/file/nigewuto.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_off00012016.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12016 17404 bytes
SHA-256: 8912dda4aaee8b36e0dc0730f60b665186e81c4e3f39f7aa5cec821d9e0399ae
font_01_sfnt_off00014d33.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14D33 10724 bytes
SHA-256: 5d15bbe5415102c4c756ed7eee305e14a0d499d17df2fa58337f1363ae70fc6e
font_02_sfnt_off000165d8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x165D8 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1