Malicious PDF — malware analysis report

Static analysis result for SHA-256 550f053a50e85ae4…

MALICIOUS

PDF

76.6 KB Created: 2021-05-19 23:29:20 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 8c4482d6fa274d18626c64362ae0aeb7 SHA-1: c914691b846c8bea0eb9aa2bfafe5e0db2ce2390 SHA-256: 550f053a50e85ae42617f87d98fb3b7401c29fcbf8be4d4bd3c021fef77f769d
156 Risk Score

Malware Insights

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

The PDF file was flagged by multiple heuristics, including ClamAV and an ML classifier, indicating malicious intent. It contains numerous external links, with one prominent URL pointing to 'zajinet.ru', suggesting a phishing or malware distribution campaign. The presence of embedded links and the PDF structure suggest it's designed to trick users into clicking malicious URLs, aligning with spearphishing tactics.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

Heuristics 5

  • 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.
  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://zajinet.ru/strik?utm_term=ielts+listening+practice+with+answers
    • https://cdn-cms.f-static.net/uploads/4375889/normal_5fdaef6cc511b.pdf
    • https://static.s123-cdn-static.com/uploads/4487916/normal_5fcc8d3e9cd42.pdf
    • https://static.s123-cdn-static.com/uploads/4530151/normal_5ff46366a51d4.pdf
    • https://cdn-cms.f-static.net/uploads/4365552/normal_606c78e810f80.pdf
    • https://cdn-cms.f-static.net/uploads/4469638/normal_606cda371ad0e.pdf
    • https://cdn-cms.f-static.net/uploads/4368768/normal_602a7161717bb.pdf
    • https://cdn-cms.f-static.net/uploads/4501229/normal_605702d07fd45.pdf
    • https://cdn-cms.f-static.net/uploads/4499282/normal_601748d5893a5.pdf
    • https://lexilovomab.weebly.com/uploads/1/3/1/4/131452944/buxasorefurijuti.pdf
    • https://cdn-cms.f-static.net/uploads/4500447/normal_60471507be0da.pdf
    • https://cdn-cms.f-static.net/uploads/4446380/normal_601eedf47423b.pdf
    • https://masodorenos.weebly.com/uploads/1/3/0/9/130969057/198cd6cbe6c9.pdf
    • https://cdn-cms.f-static.net/uploads/4476429/normal_602a001d70965.pdf
    • https://sogatawinasefe.weebly.com/uploads/1/3/4/3/134327891/8f854.pdf
    • https://cdn-cms.f-static.net/uploads/4467300/normal_5fdb1d2c3b6c9.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://uploads.strikinglycdn.com/files/481e31e0-6bf8-4b53-befa-997c4d794e34/three_levels_of_a_consumer_product.pdf
    • https://s3.amazonaws.com/vapelurowar/multiplication_worksheets_5th_grade_100_problems.pdf
    • https://uploads.strikinglycdn.com/files/f60596d4-0c2f-4db9-9397-416ebee21969/96750227909.pdf
    • https://uploads.strikinglycdn.com/files/362cfcfa-344b-4a19-9e61-c3c253a5c3f5/xixuvesivegadeguruvazo.pdf
    • https://s3.amazonaws.com/vuterijoze/ledojetamawanova.pdf
    • https://uploads.strikinglycdn.com/files/f29bdd27-1879-47b5-ae2d-9eff25f520dd/wibevobe.pdf
    • https://uploads.strikinglycdn.com/files/32e1e9f9-d930-4ee6-b203-896e9684f5c5/marbury_v_madison_case_ruling.pdf
    • https://s3.amazonaws.com/jijari/71665331588.pdf
    • https://s3.amazonaws.com/lefemijip/apus_launcher_mod_apk.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://scripts.sil.org/OFL

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000efb2.bin
0f29e747cfe0031a36f749e32d12cae5734379cf712ac9aac5e655fbac7433cf
pdf-font-stream PDF embedded font (sfnt) at offset 0xEFB2 5224 bytes
font_01_sfnt_off00010186.bin
ba202633321ee06a080cfc4fec332ed3a2243c58b901d74facfbb57d0218f6ad
pdf-font-stream PDF embedded font (sfnt) at offset 0x10186 10456 bytes