Malicious PDF — malware analysis report

Static analysis result for SHA-256 dc71eb7f75e43503…

MALICIOUS

PDF

102.7 KB Created: 2021-09-07 07:58:33 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: 7f9d6ca89143cbb9ce288747da180f57 SHA-1: 48d00b7d24fe8b6d60c894041e8523416ec47621 SHA-256: dc71eb7f75e43503c0f1cd55f7f87d72c83cdee7c22f8fd081430da9b487310d
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file is identified as malicious by ML classifiers and ClamAV, indicating a phishing or trojan threat. It contains numerous URLs, many pointing to compromised CMS upload directories or disposable hosting, suggesting a link farm designed to redirect users to malicious sites. The presence of PDF-specific heuristics like 'PDF_SEO_DISPOSABLE_LINK_FARM' and 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' strongly supports this attack pattern. No scripts were extracted, but the document structure itself is indicative of a malicious lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.7085

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
  • 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://zlhk.ru/upload_picture/file/fopegufejaramosonaj.pdf In PDF document text
    • http://huiking.cn/uploads/file/06140842716.pdfIn PDF document text
    • http://asu.com.vn/wp-content/plugins/super-forms/uploads/php/files/i4k1upvpsmiba46h8gkvacgsmi/87639605882.pdfIn PDF document text
    • http://www.akutrans.com/wp-content/plugins/formcraft/file-upload/server/content/files/160e8471243494---36668648913.pdfIn PDF document text
    • https://www.marthatrotts.ca/wp-content/plugins/formcraft/file-upload/server/content/files/1607ecedc63eae---zosuduwovol.pdfIn PDF document text
    • http://andlupa.com/userfiles/file/16910253200.pdfIn PDF document text
    • http://debeight.net/UserFiles/File/98218653764.pdfIn PDF document text
    • http://www.makattakasinti.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607fc001d1188---41250859651.pdfIn PDF document text
    • https://vetranhtuongmamnon.vn/wp-content/plugins/super-forms/uploads/php/files/lb3t5o5rtrnj35jk1qk3n7ufe0/fadanavudikejexawin.pdfIn PDF document text
    • https://www.grandiosa.is/wp-content/plugins/super-forms/uploads/php/files/mr9gjhb6k93bqoh85as7vvs0c1/49413958454.pdfIn PDF document text
    • https://tavcam.com/upload/ckfinder/files/23987683569.pdfIn PDF document text
    • https://www.shopveriamici.com/wp-content/plugins/super-forms/uploads/php/files/oj9524b5r4o7lh3vn5v6dch2vp/wimogimeneba.pdfIn PDF document text
    • http://derma-dts.de/files/file/35635424833.pdfIn PDF document text
    • http://ke-sen.com/userfiles/file/1630650594.pdfIn PDF document text
    • https://halobysciton.com/wp-content/plugins/formcraft/file-upload/server/content/files/1610e137256fe2---tapudodi.pdfIn PDF document text
    • https://plumcourse.com/wp-content/plugins/super-forms/uploads/php/files/5970ac5bc2b9669a2812a3def2280c6e/77880303653.pdfIn PDF document text
    • http://accurateverdicts.com/wp-content/plugins/formcraft/file-upload/server/content/files/16074761a260bd---koruxata.pdfIn PDF document text
    • http://vector-luczak.pl/new/fck_user_files/file/56405136669.pdfIn PDF document text
    • https://eminencesolutions.in/resources/userfiles/file/vukugusumitonefejodutot.pdfIn PDF document text
    • http://berallebags.com/UploadFiles/FCKeditor/20210709174556.pdfIn PDF document text
    • http://primaneighbors.com/userimages/73425412953.pdfIn PDF document text
    • https://www.budgetskemaet.dk/wp-content/plugins/formcraft/file-upload/server/content/files/160a226ba2a364---veredolumutamisukexabiv.pdfIn PDF document text
    • https://diarch.in/WYSIWYGImage/file/47962945390.pdfIn PDF document text
    • http://castudio.eu/userfiles/files/68161967687.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/DOqCt-cVA4I/uplcv?utm_term=direct+and+indirect+speech+in+english+grammar+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_off00012bbd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12BBD 10948 bytes
SHA-256: 30bb8c258317d94febd8f6cd83574b754abc7d06d1ab6bccf049c09fd9b9fc57
font_01_sfnt_off000144b2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x144B2 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00015cc4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x15CC4 22552 bytes
SHA-256: 56975a59cbef91515ced3713795c1654479390a2f8e0ed4cff7f30fb37223d80

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