Malicious PDF — malware analysis report

Static analysis result for SHA-256 a2a9c449eebcd656…

MALICIOUS

PDF

95.0 KB Created: 2021-07-23 09:31:59 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: ba39ee82fe14a4c7af76351323b79747 SHA-1: cbb0803ebbceac62bc9cfcfd42ed8f91402ff218 SHA-256: a2a9c449eebcd656f99da6bd9bbcf986c9fa34c52f919f62e9debcefd8b99016
156 Risk Score

Malware Insights

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

The sample is a PDF document identified by ClamAV as a phishing trojan. Static analysis revealed numerous embedded URLs, many pointing to compromised CMS upload directories or disposable hosting, indicating a link farm designed to redirect users. The ML classifier also strongly flagged this PDF as malicious. The primary attack pattern involves luring users to external sites, likely for credential harvesting or further malware delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9994

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 https://biodent.ro/m4fm_files/m4news/ck-uploads-files/54891243406.pdf
    • https://zweiund40.com/wp-content/plugins/super-forms/uploads/php/files/jdhlfnfe3rrg8jsbutslfio77u/zudazulekedifawoxineguda.pdf
    • http://reklama-v-sochi.com/ckfinder/userfiles/files/kibemu.pdf
    • http://dabaizhongxue.com/upload_fck/file/2021-6-21/20210621030006482031.pdf
    • http://globaltruthmediagroup.com/clients/a/aa/aa8380eac451876ae6ab993bf3a720d6/File/gupanekufonorom.pdf
    • http://gift-founder.com/archive/upload/files/mevusabagamibu.pdf
    • https://www.golddustdental.com/wp-content/plugins/formcraft/file-upload/server/content/files/160987478eae80---jifuxanenutix.pdf
    • https://aashianarealty.com/file/57803856790.pdf
    • http://bennett-legal.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/38140011119.pdf
    • https://kes-stv.ru/wp-content/plugins/super-forms/uploads/php/files/dfd37611c3da447338e931b60872f493/50520219806.pdf
    • https://brunoamaranti.it/wp-content/plugins/super-forms/uploads/php/files/0ut9ohltdeu4eulq9msg4pvjt3/kadavakeguzomata.pdf
    • http://amtusa.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606f752138c48---43146743638.pdf
    • http://saludocupacionalpso.com/home/wp-content/plugins/formcraft/file-upload/server/content/files/160f77320ebfa7---wanirabemugujefefowup.pdf
    • http://geose.ru/userfiles/file/womudexodib.pdf
    • http://sazjah.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609e6a20268c7---40458193863.pdf
    • https://medgarlci.com/wp-content/plugins/super-forms/uploads/php/files/06483fe9040dc1746d002467401ed0ec/ridajutolawurenupukosubu.pdf
    • http://hosungtour.com/FileData/ckfinder/files/20210712_14D9542970B8DC39.pdf
    • https://www.ogblfrontaliers.fr/wp-content/plugins/super-forms/uploads/php/files/6tqghlqsssd0dqk8bmhn5f371m/60597732260.pdf
    • http://maihome.hu/admin1/file/75733884207.pdf
    • https://777mto.info/contents//files/wugazunam.pdf
    • http://autoscuolavalerio.it/userfiles/files/marigijisivakerijumu.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/A3Ryygt5BCM/uplcv?utm_term=of+word+class
    • https://bxthirteen.wpengine.com/wp-content/plugins/super-forms/uploads/php/files/d379a25dce623a9bb56182516932ff1c/78851789584.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_off00011155.bin
5ae8217f6a1ffa20aed83317fa1d4b63e43cb459f3a40b85d455bb4e0bfc61e8
pdf-font-stream PDF embedded font (sfnt) at offset 0x11155 10156 bytes
font_01_sfnt_off0001283b.bin
85471d1037ee49217b62092b0b8ebf7281b020fe29e0f2a550548c5180a2dc57
pdf-font-stream PDF embedded font (sfnt) at offset 0x1283B 17432 bytes
font_02_sfnt_off00015605.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x15605 16792 bytes