Malicious PDF — malware analysis report

Static analysis result for SHA-256 b4c1d626a7beb662…

MALICIOUS

PDF

99.0 KB Created: 2021-04-07 00:33:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-29
MD5: 2427be8214adb0cf60dc5938093ee790 SHA-1: 4c15b52633e5efeaa8f8bb2a9ea22bdab851aac0 SHA-256: b4c1d626a7beb66210706ec8c9ab585f07edc6173e0fd14a752c4a6b7bc1d6a0
126 Risk Score

Malware Insights

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

The PDF was flagged by ClamAV as 'Pdf.Phishing.Trojan' and ML classifiers indicated a high probability of maliciousness. Heuristics identified it as a link farm on disposable hosting, with numerous external URIs pointing to various domains. The document body contains garbled text, suggesting it's not intended for direct user consumption but rather to facilitate the redirection to malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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
  • 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 http://www.muttypawsacademy.com/sites/default/files/webform/vaccines/95859103094.pdf In PDF document text
    • https://www.ofalloncasting.com/sites/default/files/webform/66890294103.pdfIn PDF document text
    • http://www.birdlifebotswana.org.bw/sites/default/files/webform/sightings-sketches/43600748611.pdfIn PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/dizage.pdfIn PDF document text
    • https://grossenbacher.co.nz/en/system/files/avoidance-training-certificates/13471650610.pdfIn PDF document text
    • http://www.guninetwork.org/system/files/webform/heirri_proposals/wozat.pdfIn PDF document text
    • https://www.osgeurope.com/sites/osg-corporate.dev/files/webform/19824824677.pdfIn PDF document text
    • http://www.pbttphtk.gov.my/sites/default/files/webform/1232685222.pdfIn PDF document text
    • http://www.pbttphtk.gov.my/sites/default/files/webform/3018222411.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://fedorahosted.org/lohitIn PDF document text
    • http://feedproxy.google.com/~r/Uplcv/~3/ngfLrbzwjls/uplcv?utm_term=the+asian+tigers+pdfPDF link annotation
    • https://campusrec.princeton.edu/system/files/webform/18758627140.pdfIn PDF document text
    • https://thesanfordschool.asu.edu/sites/default/files/webform/85266863194.pdfIn PDF document text
    • https://campusrec.princeton.edu/system/files/webform/47045932069.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

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off000115f3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x115F3 8676 bytes
SHA-256: 9bcc9206c3bc5a1ca6d3285cd7927a67d31ed6bffbfbeea52bf10db09b6558fe
font_01_sfnt_off0001333d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1333D 5220 bytes
SHA-256: d31cf09d34c9f5b99aabfb502a5515be23a6a35a984afbc31fceff3b98325056
font_02_sfnt_off000144f7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x144F7 4380 bytes
SHA-256: 5b7cfd012d648ac33342a4a37f379afe6b92284107607b9f9b0020ebde885973
font_03_sfnt_off000154d7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x154D7 13160 bytes
SHA-256: 55ecb5005c2c884d16ae4fdc5e210afe24137e06f1750b23963194700415cf92

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