Malicious PDF — malware analysis report

Static analysis result for SHA-256 81e7fd4d1c45cdc8…

MALICIOUS

PDF

87.9 KB Created: 2021-09-20 21:52:53 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 048715e27fce89a98e05dfb7264b8c5b SHA-1: ad92c9c0ec7a87a2ee97fa210a10c85ba81451a0 SHA-256: 81e7fd4d1c45cdc880ce24ad41cd5c12f1683b0445628ef7c61cda16179ba690
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous links to external websites, many of which are hosted on disposable domains or compromised WordPress sites, indicating a link farm designed to redirect users. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware distribution. Although no scripts were explicitly extracted, the PDF structure and embedded URLs are indicative of an attempt to lead the user to a malicious site.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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://catamma.ru/uplcv?utm_term=android+merge+2+photos
    • http://vina2002.com/uploads/files/99539607761.pdf
    • http://soc-in.com/data/media/files/59558927527.pdf
    • https://ooobelkom.ru/ckfinder/userfiles/files/2134233177.pdf
    • http://www.niceresidence.net/image/upload/File/46079041583.pdf
    • https://cordovajewelry.com/images/file/gujozopebipudakitopuf.pdf
    • https://vanvoorst.info/uploaded/file/bafexisitetiwi.pdf
    • https://habibitours.net/ckfinder/userfiles/files/44500190287.pdf
    • https://riwg.in/userfiles/file/33085329935.pdf
    • http://blueyee.com/upload/file/070746546243.pdf
    • https://clubselect.ro/ckfinder/userfiles/files/xititorisakemomiduligupir.pdf
    • https://vinacomvietnam.vn/uploads/news_file/lukonomejazosu.pdf
    • http://fese.in/ienupdimages/images/files/zolobososumo.pdf
    • https://luxartparquet.com/wp-content/plugins/super-forms/uploads/php/files/8659d6f4e5f999d583a610e1034e7c4d/sesajuwiwefumiximubutirun.pdf
    • http://kibunajcc.com/ckfinder/userfiles/files/49614701442.pdf
    • https://landlorddebtadvisory.com/wp-content/plugins/super-forms/uploads/php/files/73781e3e2ba9a8230d9683b0dd4c757f/satop.pdf
    • http://angel-conference.org/upload_fck/file/2021-9-5/20210905071146398620.pdf
    • http://rentbucharest.net/images/userfiles/50755738964.pdf
    • https://bonvoyageindia.in/ckfinder/userfiles/files/41820613291.pdf
    • http://vegasoft.hr/wp-content/plugins/formcraft/file-upload/server/content/files/16140c75a96b21---zaxovizusobovonaxerile.pdf
    • http://vivatbacchus.hu/files/file/39500894779.pdf
    • http://gyermekhaz.hu/Content/site_images/files/kuvodupovapegowivo.pdf
    • http://foire-fromages-et-vins.com/wp-content/plugins/formcraft/file-upload/server/content/files/16140a5ed66ac1---72109490182.pdf
    • https://sesconbs.org.br/ckfinder/userfiles/files/79172939431.pdf
    • https://lawina-radom.pl/files/file/14609877181.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://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f38d.bin
c5fd311a7e06e8026ad4584b5b21fdc433a2eaa0a4024f94774176d8d286f23b
pdf-font-stream PDF embedded font (sfnt) at offset 0xF38D 10732 bytes
font_01_sfnt_off00010bd7.bin
c8f9b9f2ae11bb127dea7d0418994c7def7788803bd10095cf114fc2e7b67c21
pdf-font-stream PDF embedded font (sfnt) at offset 0x10BD7 17620 bytes
font_02_sfnt_off000139a5.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x139A5 16792 bytes