Malicious PDF — malware analysis report

Static analysis result for SHA-256 831cecab82f47c56…

MALICIOUS

PDF

94.7 KB Created: 2021-06-18 12:26:29 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-23
MD5: 4f1e36d9abdf3eff5643e01153ca8362 SHA-1: 4be12a7c56c28654388800f397f639ae84fdd079 SHA-256: 831cecab82f47c5634294c516dfd455e68e74b8b954af3a93286a3f70bd04c4d
156 Risk Score

Malware Insights

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

This PDF file was detected as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. The heuristics reveal it functions as a link farm, directing users to multiple compromised WordPress upload directories and disposable hosting sites. The document body contains obfuscated text and what appears to be junk data, further suggesting it's designed to evade analysis and deliver a malicious payload via the embedded links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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
  • 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://markzone.az/wp-content/plugins/super-forms/uploads/php/files/fqp3re44hh9ph8r9ee14ql98jg/44292234500.pdf In PDF document text
    • http://recruiters-zone.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607d65d9dd4ad---degusekavewutuzel.pdfIn PDF document text
    • https://dungcuruamui.com/wp-content/plugins/super-forms/uploads/php/files/i7r8n3mvi1reaaoevdratpk4pa/nigutibeguwok.pdfIn PDF document text
    • http://rusiuojigalvoji.lt/wp-content/plugins/formcraft/file-upload/server/content/files/160c6691b8ce0d---34578501615.pdfIn PDF document text
    • https://daleplumbinginc.com/wp-content/plugins/super-forms/uploads/php/files/a2da66c742b90a48c352e2322c055edb/98171414383.pdfIn PDF document text
    • http://huiking.cn/uploads/file/211735026449.pdfIn PDF document text
    • https://www.superioreagle.com/wp-content/plugins/formcraft/file-upload/server/content/files/16086b6d0a2903---84121644100.pdfIn PDF document text
    • http://www.mondzorgvesa-voorschoten.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160c1a7d9663d7---13962787597.pdfIn PDF document text
    • https://floraplant.gr/FCKeditor/userimages/file/zazukijinifavudilukujiver.pdfIn PDF document text
    • https://promocionesnma.com/wp-content/plugins/super-forms/uploads/php/files/e906af99d568bbc1de4f5ea93e80b55a/80968092904.pdfIn PDF document text
    • http://www.kidnuri.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ad4053ed091---41085445946.pdfIn PDF document text
    • http://conservationenergy.com/wp-content/plugins/formcraft/file-upload/server/content/files/160be389d63864---netabiveretigidi.pdfIn PDF document text
    • https://www.diktu.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607b3a9360a04---nufubivusuvorukomusitugu.pdfIn PDF document text
    • https://primewestelectrical.com/wp-content/plugins/super-forms/uploads/php/files/5338ecb4ab7794de77b4c5f3178f3a6b/kosagujegeguvevagopu.pdfIn PDF document text
    • https://siphouse96.com/wp-content/plugins/super-forms/uploads/php/files/865671306c3e2e6b161cb4a007ba1059/nijagese.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://www.daltonmaag.com/In PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/BvfzZFkJO3s/uplcv?utm_term=two+big+black+bootyPDF link annotation
    • 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

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00012847.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12847 4604 bytes
SHA-256: f6fc1e57adca7c44647025468606aa8a0ffd8a451d2cbf0dc8af9bbdb4cee739
font_01_sfnt_off0001380e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1380E 11224 bytes
SHA-256: f4949cae0874e92db2d047e61a60a807a2707008dff1d9f80cf81536105fe853
font_02_sfnt_off00015e3a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x15E3A 4324 bytes
SHA-256: 1062cd8ddf90f4344fa193b395386d5669df1a952e5759311ca261a71931f361

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