Malicious PDF — malware analysis report

Static analysis result for SHA-256 4921d5dfa6255f98…

MALICIOUS

PDF

79.6 KB Created: 2021-09-02 17:28:51 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: 1c8e66a3ff2638cbc4a893105e957f03 SHA-1: 59d98d05e17aaf64d341056f560a7437be6a0cdd SHA-256: 4921d5dfa6255f985294c7be5554b500d4f3c936a7491b74f6bb7b6199e8e46f
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 User Execution: Malicious File

The sample is identified as malicious by ClamAV and exhibits characteristics of a link farm, with numerous URLs pointing to compromised CMS upload directories. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' indicates a pattern of using disposable hosting and UTM parameters, suggesting an attempt to obscure the true destination or to leverage SEO tactics for distribution. The presence of multiple links to compromised WordPress sites implies a phishing or scamming attempt, likely relying on user execution of the PDF to initiate further malicious activity.

Machine Learning

  • Nyx PDF Classifier suspicious score 0.4933

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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
  • PDF differential parser failed info PDF_DIFFERENTIAL_PARSE_FAILED
    The cross-check parser (pdfminer.six) failed on this file: PDF differential parser failed: PDFSyntaxError. Static heuristics still ran and any of their findings above are valid; only the differential cross-check signal is missing.
  • 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://semineebrasov.ro/printuri-fi/files/46092683199.pdf In PDF document text
    • https://www.sevgiliyevideo.net/wp-content/plugins/formcraft/file-upload/server/content/files/160bc06e9d250d---18314004964.pdfIn PDF document text
    • http://chonburi33.com/userfiles/file/59818887950.pdfIn PDF document text
    • http://chinajnbt.com/images/upload/File/kegewamifitizudixesut.pdfIn PDF document text
    • https://coebmsf.com/userfiles/file/runifulitetubowozepegabaz.pdfIn PDF document text
    • https://webmenuplus.com/images/file/71231105282.pdfIn PDF document text
    • http://furkansigorta.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/16087b73d4e665---32190564718.pdfIn PDF document text
    • http://halvani.com/wp-content/plugins/formcraft/file-upload/server/content/files/16114fedf5a127---xinipuguxufovave.pdfIn PDF document text
    • https://anzmrrn.org/wp-content/plugins/formcraft/file-upload/server/content/files/160b020cbbd967---jufogonosakaz.pdfIn PDF document text
    • https://www.lipfish.no/wp-content/plugins/formcraft/file-upload/server/content/files/160a66971c5058---lalorebirujewasupeviriv.pdfIn PDF document text
    • https://www.mercedesbenzofaustinservice.com/wp-content/plugins/formcraft/file-upload/server/content/files/16084eefac062c---2571819747.pdfIn PDF document text
    • https://gift-edu.ru/wp-content/plugins/super-forms/uploads/php/files/c2f19be59913beb6bceb6f500e7af3e8/luxesewabisanoli.pdfIn PDF document text
    • http://inlikeflintlogistics.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609c3d8db3cfa---97656279652.pdfIn PDF document text
    • http://www.teaterskolen-efteruddannelsen.dk/ckfinder/userfiles/files/75530830042.pdfIn PDF document text
    • http://www.luminicaambiental.com/wp-content/plugins/formcraft/file-upload/server/content/files/160cb0bc0574fd---melirudegalix.pdfIn PDF document text
    • http://michellenevinracing.com/FCKeditor/file/rarifamafifevowi.pdfIn PDF document text
    • https://www.weboonline.com/ckfinder/userfiles/files/39440522779.pdfIn PDF document text
    • http://akcjonariusz.com/UserFiles/file/95477483391.pdfIn PDF document text
    • https://sakitonus.ru/wp-content/plugins/super-forms/uploads/php/files/977678e39a7576fe923972adb26013d5/motabovizazalivukerudoke.pdfIn PDF document text
    • https://valserve.in/web/k/main_admin/ckfinder/userfiles/files/41415962279.pdfIn PDF document text
    • http://enidbtwcreunion.com/clients/5/52/52e94d62e82ff66504c7d921fc07bf70/File/55545960208.pdfIn PDF document text
    • https://www.generalutilities.com/wp-content/plugins/formcraft/file-upload/server/content/files/16080e74adf270---77530464079.pdfIn PDF document text
    • http://www.orarestauratorisaf.it/wp-content/plugins/formcraft/file-upload/server/content/files/16097c15285a65---batutalakojevel.pdfIn PDF document text
    • https://allcreaturesinc.com/files/files/zepirarewubav.pdfIn PDF document text
    • http://poiskvod.ru/images/file/9649821804.pdfIn PDF document text
    • http://xn----8sbpvg0afdbe.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/go1htv6u48ap5akaii7evojsp7/41965163306.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/FevRqgeaUVY/uplcv?utm_term=really+learn+english+short+stories+pdfPDF 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_off0000dd78.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDD78 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f58f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF58F 10936 bytes
SHA-256: cd97aad5a8d4cbf9499f351aff2d166605662f6deca8cdb7d6980eff9334e14b
font_02_sfnt_off00010ea2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10EA2 17204 bytes
SHA-256: 523a18c0444561662402603b81771c001cee3b121da64cf56258b0f1cde90e51

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