Malicious PDF — malware analysis report

Static analysis result for SHA-256 913fb8d8ffd71dbc…

MALICIOUS

PDF

77.3 KB Created: 2021-06-18 11:54:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-17
MD5: 193b04f4074d644ac9659e42d87cfc5f SHA-1: f48f412c4c839c5c582b76302734e8fe03993242 SHA-256: 913fb8d8ffd71dbc3a0b99da333d5077f12890f59efc10692dd9f03102d810c5
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

This PDF file was identified as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. It functions as a link farm, containing numerous URLs that point to compromised websites, likely to facilitate phishing attacks or distribute further malware. The document body itself is heavily obfuscated and contains metadata from wkhtmltopdf, suggesting it was programmatically generated to host these malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

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
  • 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://synerhu.ru/uplcv?utm_term=monster+hunter+zinogre+weakness PDF link annotation
    • https://eandjfamilyhealthcenter.com/wp-content/plugins/super-forms/uploads/php/files/aa286747e722cd18389a388537ec6129/kafepavefilanulifosivo.pdfIn PDF document text
    • https://www.infrascale.com/wp-content/plugins/super-forms/uploads/php/files/8de684abd86236e513c31a626a8a6822/31309549319.pdfIn PDF document text
    • https://shared401k.com/wp-content/plugins/super-forms/uploads/php/files/695d741681096b117b6785425961d8ae/tojexupudufopevurugoxep.pdfIn PDF document text
    • http://bergfin.se/wp-content/plugins/formcraft/file-upload/server/content/files/160833695e9d8a---zadexetebulemuluzetu.pdfIn PDF document text
    • https://kayakbranson.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c0a25cbebb3---biweguwubobozosotigusi.pdfIn PDF document text
    • http://nsfeed.com/_UploadFile/Images/file/wafosunaxuxujavinowoj.pdfIn PDF document text
    • http://diagonal.org.ar/wp-content/plugins/formcraft/file-upload/server/content/files/1607e1f21562eb---87922653695.pdfIn PDF document text
    • http://www.tif.cn/wp-content/plugins/super-forms/uploads/php/files/jm09j5ucrudb5m0ehdtibbr3d1/89870806126.pdfIn PDF document text
    • https://dedywiredja.com/wp-content/plugins/formcraft/file-upload/server/content/files/160812e8b494cf---3447596989.pdfIn PDF document text
    • http://www.sunarmisir.com.tr/wp-content/plugins/super-forms/uploads/php/files/dpju3e9voc998kci1mog0a3b75/25917120307.pdfIn PDF document text
    • https://keluargamimpi2.com/contents//files/kalizamuwekuno.pdfIn PDF document text
    • http://www.hkwebdesign.com.hk/wp-content/plugins/formcraft/file-upload/server/content/files/1607ddb6f62535---25356627873.pdfIn PDF document text
    • https://controlcert.se/wp-content/plugins/formcraft/file-upload/server/content/files/1607dc188cebdf---48319837593.pdfIn PDF document text
    • https://castel.ro/userfiles/file/89300933353.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://scripts.sil.org/OFLIn PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d33f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD33F 2984 bytes
SHA-256: 622b466b7c13a7bb696b1bf92837937af37c3c6e583ed1988075f1b162750079
font_01_sfnt_off0000ddc6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDDC6 5128 bytes
SHA-256: 452ed0fd6ff5b39485c2633d63b151d9e0fbbecb296d786124f65c2bf9f0ed2b
font_02_sfnt_off0000ef56.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEF56 10268 bytes
SHA-256: 6967312ac8affc6a985f1e45ec00eb1c2c6f749bc0034502e69f4538e0db0fb1
font_03_sfnt_off000112ab.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x112AB 16192 bytes
SHA-256: c5d15a1fcaf4a0b55ddb2a15e31956da69ccbf4f4eb3af1b0329a8a01b37e6a7

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