Malicious PDF — malware analysis report

Static analysis result for SHA-256 337c71abe2aae33d…

MALICIOUS

PDF

96.4 KB Created: 2021-07-18 15:50:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 0017fcc8b66a2c148bc2dd9f3a11cb5a SHA-1: dc13e78ef16e4c401a4ea2cff5fedb8eb44f9b7b SHA-256: 337c71abe2aae33d1dffba82739153d168027794a33777461fc3007cc87b2a27
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Several heuristics point to the PDF being a link farm hosted on compromised or disposable domains, suggesting it's used to redirect users to malicious content. The presence of external URIs and a compromised CMS upload link further supports this. While no scripts were explicitly extracted, the PDF structure and link farm behavior are consistent with phishing or malware distribution campaigns.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9820

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
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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://kipia-nn.ru/userfiles/file/94970084492.pdf
    • https://chmelo.hu/sites/default/files/file/31384832119.pdf
    • http://cassotech.nl/site/data/ws/files/33746094795.pdf
    • https://mamo-tato.ro/userfiles/file/23557217290.pdf
    • http://guanzhuli.com/userfiles/file/63847805952.pdf
    • http://www.asslar.de/downloads/tadum.pdf
    • http://sirmamedia.com/ckfinder/userfiles/files/7633461072.pdf
    • http://bodymindspiritconnection.org/clients/5/53/53f1eac0d8ee32431a47b4e1af774f29/File/69473275376.pdf
    • http://mirrorgallery.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c53066b0e09---20892444404.pdf
    • http://aivieksteslaivas.lv/userfiles/file/kegilixopedel.pdf
    • http://westmoorclassof1965.com/clients/5/52/52ec68f2b927accf75267cb07bfcc891/File/jomenawikikavalujimek.pdf
    • http://vtracauto.com/wp-content/plugins/formcraft/file-upload/server/content/files/16085beded2829---famavutoxenap.pdf
    • http://freemansphotography.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608ce203bf67e---89728869094.pdf
    • http://montaze.org/democms/userfiles/file/sodina.pdf
    • http://janatalnajaf.com/basefile/janatalnajafcom/files/89550680330.pdf
    • https://criteriacambio.com.br/wp-content/plugins/super-forms/uploads/php/files/5p8ih7tl0cgrttjsaifcko1214/mezarotoz.pdf
    • http://www.toeterloeh44.de/files/80725370253.pdf
    • https://moveo-sport.pl/userfiles/file/gigozulok.pdf
    • http://hoondb.com/wp-content/plugins/formcraft/file-upload/server/content/files/160892424b6afc---24435873735.pdf
    • http://hobbstownis100.com/clients/6/66/66141d04a4341350d76ae3a38785cb5a/File/sewew.pdf
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/160f09dac20f28---12617655827.pdf
    • https://alphaveneers.co.uk/wp-content/plugins/super-forms/uploads/php/files/6a4ece22e8e20bd3400187fde8bba802/18351755090.pdf
    • https://moveo-sport.pl/userfiles/file/rikowepevigal.pdf
    • https://christembassybarking.org/wp-content/plugins/super-forms/uploads/php/files/72e0c94bded87af7aba1a0d80061e461/jerogiwidofujeduzumat.pdf
    • http://aclamerica.com/customers/CMS-IMAGES/file/siturabe.pdf
    • https://engravestone.com/wp-content/plugins/formcraft/file-upload/server/content/files/16074c1669d8bf---70968900749.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/A3Ryygt5BCM/uplcv?utm_term=research+paper+on+global+warming+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://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_off000115d1.bin
1c089baab9f25d56e6a962e2e62d0af191d2ac75a6e29d1e295f7b1063d8162c
pdf-font-stream PDF embedded font (sfnt) at offset 0x115D1 16892 bytes
font_01_sfnt_off000141e4.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x141E4 16792 bytes
font_02_sfnt_off000159fb.bin
e73879f5c6c128fe8173e70f50f35aee8b15cd4a345ed7054a0dce30540362c5
pdf-font-stream PDF embedded font (sfnt) at offset 0x159FB 11240 bytes