Malicious PDF — malware analysis report

Static analysis result for SHA-256 cb771b31e9960f1f…

MALICIOUS

PDF

81.8 KB Created: 2021-09-09 15:52:49 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: d5beca7347b98b6e7a26271ad1bc0c53 SHA-1: 836e8a7ebf6f26c6df6b12b9cdb819cc00b39ac7 SHA-256: cb771b31e9960f1f2d9cd2e437796e747714c351d992441484bcc77728d03e31
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by multiple heuristics, including a critical ClamAV detection and an ML classifier, indicating malicious intent. It contains numerous embedded URLs, with one heuristic specifically identifying it as a link farm on disposable hosting. While no scripts were explicitly extracted, the PDF structure and embedded URLs suggest it's designed to redirect users to potentially malicious sites, aligning with phishing or malware delivery tactics.

Machine Learning

  • Nyx PDF Classifier malicious score 0.6197

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
  • 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 http://hanhthien.net/uploads/file/sudimejekita.pdf In PDF document text
    • https://htcpost.vn/vietpost.vn/img_content/file/63752007337.pdfIn PDF document text
    • https://kildevangen.dk/files/34088499227.pdfIn PDF document text
    • http://turksebruiloften.nl/userfiles/file/53545921102.pdfIn PDF document text
    • http://sprostredkovanieuverov.sk/res/file/mizumapozinosusadozavi.pdfIn PDF document text
    • http://lavera.it/wp-content/plugins/formcraft/file-upload/server/content/files/161338c1e11efe---lopubovilegasudesunumanu.pdfIn PDF document text
    • https://minlinart.com/archive/upload/files/47870302492.pdfIn PDF document text
    • http://noithatlekhanh.com/Images_upload/files/30552326584.pdfIn PDF document text
    • https://butterfly-propertymanagement.com/userfiles/file/62946557261.pdfIn PDF document text
    • http://www.louisianarebarcontractor.com/editorimg/file/39249757824.pdfIn PDF document text
    • https://bestcaps99.com/ckfinder/userfiles/files/26983796623.pdfIn PDF document text
    • https://rainbowfurnitures.com/files/files/gurudul.pdfIn PDF document text
    • http://kibunajcc.com/ckfinder/userfiles/files/16501900662.pdfIn PDF document text
    • http://bestofbeer.ru/ckfinder/userfiles/files/72459649868.pdfIn PDF document text
    • http://massintech.ru/img/outer/files/29898967554.pdfIn PDF document text
    • https://afmiletisim.afmiletisimajansi.info/resimler/files/babevivimelilisedubopajuv.pdfIn PDF document text
    • https://zivotzaokny.eu/res/file/60830878228.pdfIn PDF document text
    • https://pima-alarms.eu/slicice/file/kovabegabajalunorokik.pdfIn PDF document text
    • http://greatwalledmond.com/ckfinder/userfiles/files/zozikamevem.pdfIn PDF document text
    • https://kubermatkaplay.com/ckfinder/userfiles/files/movep.pdfIn PDF document text
    • https://denizlihorozu.com/resimler/files/72912372371.pdfIn PDF document text
    • https://bankubezpieczen.pl/userfiles/file/33227415753.pdfIn PDF document text
    • http://chiaranannini.com/userfiles/files/ravufunexumonimedewoxurep.pdfIn PDF document text
    • https://nabsangram.com/userfiles/file/juwagit.pdfIn PDF document text
    • http://dtpokebar.com/uploads/files/sakobuwadixun.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/zMnd8XtcwSM/uplcv?utm_term=java+gson+create+json+objectPDF 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_off0000e7ba.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE7BA 10592 bytes
SHA-256: f295ebb2824669c116f564b42de6698e21da4cd9719092507658f17627a0ed9c
font_01_sfnt_off0001002c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1002C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0001183e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1183E 16996 bytes
SHA-256: 3d2c031c13d8d0354f1f99e2b9c56419c9875f5575b7e6943a6f961cc3b46813

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