Malicious PDF — malware analysis report

Static analysis result for SHA-256 2138c544f7b92db9…

MALICIOUS

PDF

80.2 KB Created: 2021-09-18 23:17:44 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 59881482384dc5daf20a3f035e704c2b SHA-1: f09eb2f88414fc60327f95b4780d61b4cd5302e7 SHA-256: 2138c544f7b92db9fc75f008e1f75213b41f8d9a4777f7bb0d4ae463e43a1617
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The file is identified as malicious by ClamAV and an ML classifier. It contains numerous external URIs and link farms pointing to various PDF files, some hosted on what appear to be compromised CMS upload directories. The presence of multiple PDF files hosted on different domains suggests an attempt to distribute malicious content or engage in SEO poisoning.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9911

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://beysukonaklari.com/ckfinder/userfiles/files/pomusagukamufup.pdf
    • https://www.bramfordgc.co.uk/ckfinder/userfiles/files/nexaf.pdf
    • http://imi.vc/upload/files/66836518341.pdf
    • https://harom.ro/files/file/vegoz.pdf
    • http://didongsinhvien.com/upload/files/70630816201.pdf
    • http://atomleasing.ru/media/File/77942622595.pdf
    • https://5udua.com/contents/files/pirotejetofonovuxamek.pdf
    • http://tgroupsrl.com/userfiles/files/52398512269.pdf
    • http://karthikeyanjayaram.com/userfiles/file/55061405840.pdf
    • https://yournew.site/wp-content/plugins/super-forms/uploads/php/files/jgp62km2gdk3tp5ra45vimhhj2/vasirivuzijixem.pdf
    • https://detectagsafety.com/ckfinder/userfiles/files/64810069206.pdf
    • https://www.euroservicemilano.it/wp-content/plugins/formcraft/file-upload/server/content/files/1614061e26bbcf---savuvixodivafujelotu.pdf
    • https://roadtoring.com/wp-content/plugins/super-forms/uploads/php/files/4e7da71205aa002afbae0bbc8c1c7299/36094224609.pdf
    • https://interativacorretora.com/fotosempresa/files/32889348972.pdf
    • https://stonebuild.bg/f/uploads/files/buriwemefu.pdf
    • http://mgtuae.com/uploads/file/41841304600.pdf
    • http://onlinemidias.com/ckfinder/userfiles/files/vifutupobitiporunazep.pdf
    • https://laurallo.com/ckfinder/userfiles/files/bozijajijode.pdf
    • https://lufty.cz/UserFiles/files/bafopi.pdf
    • http://simkoongschool.com/uploads/editer/files/nefadixidomiwunutuveze.pdf
    • http://studiobonvino.com/userfiles/files/wakogad.pdf
    • https://projektovanje.info/userfiles/file/kikafatumeku.pdf
    • http://kodemari.info/data/files/11934547043.pdf
    • http://energy-labels.com/userfiles/file/12069991632.pdf
    • http://energo-market.ru/sadm_files/86286982841.pdf
    • https://sweetestspaparty.com/wp-content/plugins/formcraft/file-upload/server/content/files/16134ec3877cff---kitizowo.pdf
    • https://baoyi-chuck.com/ckfinder/userfiles/files/dinunewubakoregote.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/6naE_Nh8_CY/uplcv?utm_term=potong+video+android
    • 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_off0000d82c.bin
e58e99ee3b295a2e1f5bd5dfaea725640715a9bb20326af0d102e6b8de81b087
pdf-font-stream PDF embedded font (sfnt) at offset 0xD82C 10276 bytes
font_01_sfnt_off0000ef40.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xEF40 16792 bytes
font_02_sfnt_off00010752.bin
03ae88549748424c68c274494190efda6cba77f6b01010f72768bd873efb5dbf
pdf-font-stream PDF embedded font (sfnt) at offset 0x10752 16868 bytes