Malicious PDF — malware analysis report

Static analysis result for SHA-256 51116f01d9047b3e…

MALICIOUS

PDF

67.5 KB Created: 2021-03-14 19:10:55 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-08-25
MD5: 37904ee894943fa22c92a3a83752eca9 SHA-1: ddd0a52fb788f93cbbc36cbd688bfa00b4602bef SHA-256: 51116f01d9047b3e3a8eb3c106e326d9b3f9ad5ac3750b5eb23fabc415bdec4d
126 Risk Score
Tags
free-cdn-ebook-manual-lure

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, indicating a high likelihood of malicious intent. It contains numerous embedded URLs pointing to disposable hosting and link farms, suggesting a phishing or malware distribution scheme. The document body, though heavily obfuscated, contains text related to 'worksheet answer key' and 'wkhtmltopdf', which is likely a lure to entice users to click on the malicious links.

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 https://maypoin.ru/wix?keyword=surface+area+nets+worksheet+answer+key PDF link annotation
    • https://visepawil.weebly.com/uploads/1/3/0/7/130776118/3611434.pdfIn PDF document text
    • http://worldthailand.fun/marxism_theory_definitionksr1g.pdfIn PDF document text
    • https://mebijanuwirat.weebly.com/uploads/1/3/4/0/134042853/zerusatokolazegex.pdfIn PDF document text
    • https://polemezal.weebly.com/uploads/1/3/1/4/131452876/xutevoriwu_rigaxobitez_sumovovazi.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4412895/normal_5fe1d8afc0f51.pdfIn PDF document text
    • http://cetakchantek.com/kizudufifogojikuxuzewphg9b.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4474222/normal_600b71201963a.pdfIn PDF document text
    • http://flymoney.net/69762481620hb08z.pdfIn PDF document text
    • https://xagigerabep.weebly.com/uploads/1/3/1/4/131483632/sozixufoge.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4482399/normal_5ffd4b9247268.pdfIn PDF document text
    • http://snapchat-alert.com/fetikajoloxih6kb6.pdfIn PDF document text
    • https://gejeliruvuke.weebly.com/uploads/1/3/4/6/134699680/3824708.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4451566/normal_6036d3cc60878.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4485711/normal_5ff2a09cb40fa.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4452374/normal_5ffe547013fff.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/jeworurowam/95426416160.pdfIn PDF document text
    • https://s3.amazonaws.com/fatikonavori/12333534654.pdfIn PDF document text
    • https://s3.amazonaws.com/wipotegadodorek/45393651338.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_off0000cb3a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCB3A 5296 bytes
SHA-256: f44c2a6311da7fbdebc651cf13cb93a69c5c92d42c3d6ac859909bf05c1aaa4c
font_01_sfnt_off0000dd4f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDD4F 10412 bytes
SHA-256: f49f0faf00799bae09d90672a382c6e74dadf6f573290bfec76e6a2acb109ccf

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