Malicious PDF — malware analysis report

Static analysis result for SHA-256 b4af2822cfc9ead0…

MALICIOUS

PDF

74.1 KB Created: 2021-01-16 12:47:32 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-05
MD5: b8a42341e09a9436b95dc33d41c286cf SHA-1: 9dd9d59ef27c826a3d33eed98d4b51f547baa554 SHA-256: b4af2822cfc9ead0570c7e7cf7c55ff61ebde3db1d071a5df73b2deb57951cf4
186 Risk Score
Tags
free-cdn-ebook-manual-lure

Malware Insights

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

The PDF document contains a large number of external links, many hosted on disposable domains, indicating a link farm or phishing attempt. The document body, though heavily obfuscated, suggests a lure related to 'Blackboard' to direct users to malicious URLs. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for malware distribution or credential harvesting.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 6

  • 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 contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • 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://traffking.ru/123?utm_term=how+to+edit+or+delete+a+thread+on+blackboard PDF link annotation
    • https://vubibawijov.weebly.com/uploads/1/3/0/7/130776162/xemewivemixedi-bikunimajudom.pdfIn PDF document text
    • https://lemusovigezamo.weebly.com/uploads/1/3/1/3/131381045/xifabikix.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4501029/normal_5ff600c8e51ed.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4403685/normal_5ffbf2ffb2f64.pdfIn PDF document text
    • https://cdn.sqhk.co/poxofufiko/ih5hji6/10819206497.pdfIn PDF document text
    • https://papunagaku.weebly.com/uploads/1/3/1/3/131384156/xalipubow.pdfIn PDF document text
    • https://ruzuxopamekegi.weebly.com/uploads/1/3/4/7/134748505/2571377.pdfIn PDF document text
    • https://matekulelesij.weebly.com/uploads/1/3/4/8/134858821/5815204.pdfIn PDF document text
    • https://cdn.sqhk.co/zururodi/zeihehi/povexagipawowovotag.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4450260/normal_5fbf4dbd49188.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4372354/normal_5f9b31ff73d3b.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/fekaduvopigab/usmle_score_conversion.pdfIn PDF document text
    • https://s3.amazonaws.com/pewibim/84500482143.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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e753.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE753 5104 bytes
SHA-256: 74d85e566e0b9da629b0f1eb957b1eae87275032cf225e389aa96e7123939a9d
font_01_sfnt_off0000f8b5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF8B5 10284 bytes
SHA-256: b417825f74f79fd422a030997d5b43c83259f47b37bf2947415d59415d2cac65

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