Malicious PDF — malware analysis report

Static analysis result for SHA-256 a1139e0a435ede61…

MALICIOUS

PDF

73.1 KB Created: 2021-04-10 15:55:04 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-29
MD5: 41ef6b90b6994defe4b063eeeeb33831 SHA-1: ed23dfa655cbebf5f4870ed816525dc8c7204717 SHA-256: a1139e0a435ede61de68f9c46fd07fc5f8c15fe7b31ec70dfc5aa119ccf9321c
126 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many pointing to what appears to be a link farm designed to obscure the ultimate destination. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' strongly suggests a malicious intent to redirect users. While no scripts were explicitly extracted, the nature of the embedded links and the ML classifier's high confidence indicate a phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://seiary.com/sites/default/files/webform/rec/55418097166.pdf In PDF document text
    • https://ambrose.edu/sites/default/files/webform/46846662681.pdfIn PDF document text
    • http://www.pbttphtk.gov.my/sites/default/files/webform/42283273604.pdfIn PDF document text
    • https://web.liderpapel.com/sites/default/files/webform/wavunivuzabanovomid.pdfIn PDF document text
    • https://www.visitsavannah.com/sites/default/files/webform/59391310887.pdfIn PDF document text
    • http://www.pbttphtk.gov.my/sites/default/files/webform/88462653206.pdfIn PDF document text
    • http://seiary.com/sites/default/files/webform/rec/47545977947.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/26147793628.pdfIn PDF document text
    • https://web.liderpapel.com/sites/default/files/webform/21411595718.pdfIn PDF document text
    • http://oaklandchildcare.org/sites/default/files/webform/55178968397.pdfIn PDF document text
    • https://www.a1touchsolution.nl/sites/default/files/35095474677.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/vopezupudatirarib.pdfIn PDF document text
    • https://www.ofalloncasting.com/sites/default/files/webform/mibotemesasis.pdfIn PDF document text
    • https://www.woonsocketri.org/system/temporary/webform/viwubamonutimujogigifowi.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/skout/mBVl/~3/cv9VXjIrmdE/uplcv?utm_term=dise%25C3%25B1o+de+losas+de+concretoPDF link annotation
    • https://campusrec.princeton.edu/system/files/webform/rilawadabovoxilezevateg.pdfIn PDF document text
    • https://lib.asu.edu/system/files/webform/liwubuwivak.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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d428.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD428 4932 bytes
SHA-256: 1060200e86ff4a8f0fc9bac685f17e8a8ec8fbc5f034fa8546e11eb8f301bc4c
font_01_sfnt_off0000e4ab.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE4AB 10712 bytes
SHA-256: b3df21b2981c1a4762c30b908f3267eb74db9ce9c433a7ddab185a177f40884f
font_02_sfnt_off00010796.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10796 4324 bytes
SHA-256: 1062cd8ddf90f4344fa193b395386d5669df1a952e5759311ca261a71931f361

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