Malicious PDF — malware analysis report

Static analysis result for SHA-256 9f5158172e7fe0eb…

MALICIOUS

PDF

77.9 KB Created: 2021-02-17 17:21:33 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-03
MD5: 5c993d73fc8597abe9f1ed20480b4df4 SHA-1: 8a6635dd50f3bbabfa19399632babedc0ed3651c SHA-256: 9f5158172e7fe0eb286c0fdfa45cb812766cfc18864cdcd086b9e84e23d5662a
154 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The PDF contains a critical heuristic firing for a malicious redirector link pointing to 'https://yafferge.ru/aws?utm_term=how+to+critically+assess+a+research+paper'. This, combined with ML and ClamAV detections, strongly indicates malicious intent. The document body is heavily obfuscated, but the presence of embedded URLs and the redirector link suggest the primary goal is to lure the user to a compromised site. No scripts were extracted, so the attack vector is presumed to be the embedded link.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 4

  • 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 links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK
    PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
  • 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://yafferge.ru/aws?utm_term=how+to+critically+assess+a+research+paper In PDF document text
    • https://static.s123-cdn-static.com/uploads/4487662/normal_5ff783a7030dc.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4470400/normal_6003b27b7b29d.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4393179/normal_60107f8e96222.pdfIn PDF document text
    • http://money-team.site/fuentes_fijas_de_contaminacion_del_airepkr9q.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4413564/normal_6011dfdd8d6fd.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4365642/normal_5fe7cd1e138bd.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4456399/normal_5ff857ba3c45e.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4469640/normal_5fec04d381b47.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4450141/normal_5fd6f9e39691d.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://s3.amazonaws.com/jovekus/nafibugaj.pdfIn PDF document text
    • https://s3.amazonaws.com/xajowu/call_recorder_acr_license_apk.pdfIn PDF document text
    • https://s3.amazonaws.com/wajufifenoxuj/66486719327.pdfIn PDF document text
    • https://s3.amazonaws.com/tasufagijaremo/anemia_pathology.pdfIn PDF document text
    • https://s3.amazonaws.com/sepawi/ekonomiks_teaching_guide_part_6.pdfIn 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e168.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE168 5176 bytes
SHA-256: a93f1175b01a224b359fcaadd84e6cab5bbccb7bf9e21dcb8824c4cc81dfe13f
font_01_sfnt_off0000f313.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF313 10160 bytes
SHA-256: cb971a2ba240ebd5290e9a423cb8ed5ebe271ca227bd7adb2a5bd51872a59ff6
font_02_sfnt_off00011623.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11623 16028 bytes
SHA-256: 0bae8649ba252bcfab81cb8324cfe1737d73e47191b507e117e6d0858e0066a8

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