Malicious PDF — malware analysis report

Static analysis result for SHA-256 a72f08b8b4bfe4c5…

MALICIOUS

PDF

85.5 KB Created: 2021-01-19 05:51:29 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-03
MD5: c37be3ef35f62ff47306f924b1f04d11 SHA-1: 81ee39d10b775654d624a342d4aae2ae8eab3dcf SHA-256: a72f08b8b4bfe4c56372defcbe2d0a8accb779adea1c86741206a6ccc0bdb487
126 Risk Score

Malware Insights

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

The PDF file is detected as malicious by ML classifiers and ClamAV, indicating a phishing or trojan payload. It contains multiple embedded URLs, with one specifically linked to a 'letter of recommendation for nursing school' lure, suggesting a social engineering tactic. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' further indicates a malicious intent to distribute links across disposable hosting, likely for phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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 https://leonvi.ru/123?utm_term=letter+of+recommendation+for+nursing+school PDF link annotation
    • https://site-1168118.mozfiles.com/files/1168118/babidoxox.pdfIn PDF document text
    • https://cdn.sqhk.co/romumoxoleno/1aXhgfk/yellow_wallpaper_quotes_about_john.pdfIn PDF document text
    • https://cdn.sqhk.co/fedelubu/RgcjbeX/27613067011.pdfIn PDF document text
    • http://xurufotuzu.iblogger.org/acls_algorithms_aha.pdfIn PDF document text
    • https://site-1245341.mozfiles.com/files/1245341/gastroenteritis_viral_fisiopatologia.pdfIn PDF document text
    • https://site-1180682.mozfiles.com/files/1180682/vivaldi_previous_version.pdfIn PDF document text
    • https://cdn.sqhk.co/xogeloke/hfijewc/54875831709.pdfIn PDF document text
    • https://site-1172077.mozfiles.com/files/1172077/51353351598.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4446782/normal_5fb57d35d1ab8.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
    • http://napilidowolaro.rf.gd/char_broil_grill_performance_series_parts.pdfIn PDF document text
    • http://dazulenaredon.rf.gd/6150911619.pdfIn PDF document text
    • http://mowumaja.epizy.com/84461299312.pdfIn PDF document text
    • http://dorowoz.rf.gd/nfl_kc_injury_report.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_off00010405.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10405 5256 bytes
SHA-256: e6cfc18d5d1885f1e8ea6d20c7a914ba3971ce8f6b43f3ef27467704666ddf14
font_01_sfnt_off000115b0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x115B0 10764 bytes
SHA-256: caf3c3305529b645fd9011ef1dbaf3de42349dea89304b7e1bd7317c6b864073
font_02_sfnt_off00013a4d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13A4D 4324 bytes
SHA-256: b50a2106bf82917db0cd3cf88f63c5e8cc3298b343ace5cffc591b35df33d24c

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