Malicious PDF — malware analysis report

Static analysis result for SHA-256 4a5a251507b7d3a7…

MALICIOUS

PDF

80.7 KB Created: 2021-09-18 08:23:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 2bb629f2a30e85646f824af0b63b09a3 SHA-1: 1f21b46b6ab7d70d1ec5e92cf1e87dc1d6ebc0a4 SHA-256: 4a5a251507b7d3a793bcbacd166109cbaba20da72e4c756a1a42c9430195232c
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF was flagged by ML classifiers and ClamAV as malicious, exhibiting characteristics of a link farm. It contains numerous embedded URLs pointing to other PDF files hosted on various domains, suggesting a phishing or malware distribution campaign. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' indicates a deliberate attempt to create a large number of links on potentially disposable hosting, further supporting this assessment.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

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://villacappuccina.com/userfiles/files/31143475473.pdf
    • http://steelfurniturecn.com/d/files/30418355236.pdf
    • https://riolospettacoli.it/filesUploads/file/duzimolitejafolafakolalep.pdf
    • https://supermagnum-bg.com/userfiles/file/befododepororoninelelilu.pdf
    • https://www.psk.com.au/application/third_party/ckfinder/userfiles/files/sogopavixenufe.pdf
    • http://aytekinpolatel.com/image/files/ronapuvinekewov.pdf
    • https://gegeny.hu/uploads/file/wizofekejijevabokarusewu.pdf
    • http://celyroknaterase.sk/editor_uploads/system/files/lewavabogavi.pdf
    • http://thietkewebbacninh.com/webroot/img/files/zobuxuvojemos.pdf
    • http://zhengfutz.com/v15/Upload/file/2021910132664314.pdf
    • http://abwhopewell.com/uploads/files/dafademezomevekor.pdf
    • https://autopits-directo.migrupoq.com/ckfinder/userfiles/files/nanitorozadevotuzawaxoxij.pdf
    • http://matras-devison.com/upload/file/gozetepabejenalomusufefo.pdf
    • http://4998horo.gmmwireless.com/contents/files/56203058742.pdf
    • https://dascalita.ro/app/webroot/files/userfiles/files/68206415805.pdf
    • http://verzorgingsindex.nl/images/uploads/mutaluruwepirinemukexisuw.pdf
    • https://foundlight.ca/home/foun6192/public_html/files/custom_files/file/wuzikolijapifakolewi.pdf
    • http://qdjshg.com/files/file/75138143523.pdf
    • http://mrpennarak.com/user_file/file/97256249301.pdf
    • https://izometal.net/mm/file/1612552424.pdf
    • http://www.swaving-stalinrichting.nl/ckfinder/userfiles/files/30871913355.pdf
    • https://stancijanegrin.com/UserFiles/files/78388087195.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/BvfzZFkJO3s/uplcv?utm_term=edit+android+contacts+on+pc
    • 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://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d7da.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1		 pdf-font-stream PDF embedded font (sfnt) at offset 0xD7DA 16792 bytes
font_01_sfnt_off0000eff1.bin
c41fe6ed6e80c4e8518b20b008e07035e8b30c7a81649045fd38688aa6039beb		 pdf-font-stream PDF embedded font (sfnt) at offset 0xEFF1 10312 bytes
font_02_sfnt_off00010741.bin
517888bfa5cbd1fff1236651fd3150fd3f4539371227e4bcd66362b38071df7f		 pdf-font-stream PDF embedded font (sfnt) at offset 0x10741 17624 bytes

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