Malicious PDF — malware analysis report

Static analysis result for SHA-256 8f5741304ddd8640…

MALICIOUS

PDF

72.1 KB Created: 2021-10-02 12:35:20 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: ead8711e073c6006430e58dc08f328a0 SHA-1: afd77db99ca505dd5ea11ec382d543f4f56f2e5a SHA-256: 8f5741304ddd864088bc32b02ea03034e4e5994f1b6a14f702e90ad2602a151c
176 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains numerous embedded URLs, many of which point to compromised or disposable hosting, indicating a link farm designed to redirect users to malicious content. The ClamAV detection and ML classifier further support its malicious nature. The malformed stream length heuristic suggests an attempt to exploit PDF parsing vulnerabilities.

Machine Learning

  • Nyx PDF Classifier malicious score 0.8252

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • Malformed active-content stream length medium PDF_MALFORMED_EXPLOIT_STREAM_LENGTH
    A PDF stream that carries active/exploit-looking content has a declared /Length that does not match the recovered stream body. Malformed stream boundaries and length mismatches are common parser-evasion/supporting evidence around Reader exploit streams.
  • 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 http://plkorea77.com/ckupload/files/ziwupulorug.pdf In PDF document text
    • http://mesotects.com/wp-content/plugins/formcraft/file-upload/server/content/files/16138cf647ac18---5446716522.pdfIn PDF document text
    • https://www.beewellrx.com/wp-content/plugins/super-forms/uploads/php/files/l78b43qho6qjg3dcqh4s2flaqlm171cg/mamelogibe.pdfIn PDF document text
    • http://gerocuki.hu/user/file/losepokotodoworel.pdfIn PDF document text
    • http://turystyka.powiatlubartowski.pl/admin/ckfinder/userfiles/files/vozesogumimenufi.pdfIn PDF document text
    • https://www.denisonlandscaping.com/wp-content/plugins/formcraft/file-upload/server/content/files/161570a9c84d6c---50244632770.pdfIn PDF document text
    • http://drapa-technika.cz/UserFiles/File/jonitigegizidajobuzulukuv.pdfIn PDF document text
    • http://langeline.com/ckeditor/upload/files/74895232051.pdfIn PDF document text
    • http://www.garriagricola.com/wp-content/plugins/formcraft/file-upload/server/content/files/1615034937e8ef---lazejivigatumikojisop.pdfIn PDF document text
    • http://metzpaintings.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612fbd20e2420---57680260848.pdfIn PDF document text
    • https://autohausnschmidt.de/userfiles/file/gowebigoveled.pdfIn PDF document text
    • http://jsushibrea.com/uploads/files/lirukunalovoz.pdfIn PDF document text
    • http://commissioncollectionlaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/mejunadiditamotozizuxeza.pdfIn PDF document text
    • https://citrasas.com/userfiles/file/miwogabus.pdfIn PDF document text
    • http://medicom.pl/userfiles/file/vegejenukatojalawukemaz.pdfIn PDF document text
    • http://fu-xin.tw/uploads/files/202109130236488786.pdfIn PDF document text
    • http://www.everhouse.lt/wp-content/plugins/formcraft/file-upload/server/content/files/1614ee63192557---velitutabinemaluwi.pdfIn PDF document text
    • https://gpagroup.in/wp-content/plugins/formcraft/file-upload/server/content/files/1613604dc9378a---72108934290.pdfIn PDF document text
    • http://cngwalk.com/fckeditor/userfiles/image/gumesotakiru.pdfIn PDF document text
    • https://securitydm.eu/slicice/file/97314771670.pdfIn PDF document text
    • https://cauthinh.com/luutru/files/lobetokuxenumiwedine.pdfIn PDF document text
    • https://fitvital.hu/userfiles/files/44688540570.pdfIn PDF document text
    • http://goang-hann.com/uploads/files/202109041509125315.pdfIn PDF document text
    • https://aldurra.ly/images-editeur/img/file/97984169858.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/ngfLrbzwjls/uplcv?utm_term=universal+serial+bus+devices+windows+10PDF link annotation
    • 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_off0000b9df.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB9DF 18388 bytes
SHA-256: 99f01d8245037491900a148d43f97ff364b8458e6fc8a3dfeb65b1aa1bb0d02d
font_01_sfnt_off0000e90f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE90F 10836 bytes
SHA-256: abbae11b19a37e820ddde3f0c3322ff3a7603d5c8b5d1df45609bd835568d9d7
font_02_sfnt_off00010243.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10243 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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