Malicious PDF — malware analysis report

Static analysis result for SHA-256 31882ab1093a30d5…

MALICIOUS

PDF

80.0 KB Created: 2021-07-17 00:25:55 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 6709f91a252f5182c8d6d2e854c326ee SHA-1: 14b29c3344227e33c5b7c899e90f9fd0f53408f2 SHA-256: 31882ab1093a30d5c3f430387031e0322e3214643bb80113bd355410143dbfa9
156 Risk Score

Malware Insights

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

The PDF document contains a large number of external links, many of which point to compromised WordPress sites hosting other PDF files. The ML classifier and ClamAV detection strongly indicate malicious intent, likely to lure users to malicious content or phishing pages. No scripts were extracted, but the link farm structure itself is the primary attack vector.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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://www.cdscabling.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1607763f27eaed---xovosubo.pdf
    • https://cortopolis.ar/userfiles/file/72978715092.pdf
    • http://www.olympussverige.se/wp-content/plugins/super-forms/uploads/php/files/510d04f1a6uimat6ks049teiu2/zizijunaninawu.pdf
    • https://dsodrecital.com/wp-content/plugins/formcraft/file-upload/server/content/files/160edc35b00971---3231342732.pdf
    • https://www.finestkindcharter.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607d918605ce3---sofevomoverelarotakura.pdf
    • https://salubrismd.com/wp-content/plugins/super-forms/uploads/php/files/33ab88be27d40529cabb9bee57f84f6b/neragisuvobikev.pdf
    • https://luxurytravel-show.com/wp-content/plugins/super-forms/uploads/php/files/866ff47692964c723e4f112209d583d3/82751939820.pdf
    • https://afayl.com/userfiles/file/14859820755.pdf
    • http://expresskaliski.info/file/kifodomezipuwop.pdf
    • https://saraelv.no/wp-content/plugins/formcraft/file-upload/server/content/files/16071b6ad42b14---sosub.pdf
    • http://jshtextile.com/UserFiles/file///pipose.pdf
    • http://cetinelektrik.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/16086d1be9ee58---masorukapunomopoxa.pdf
    • https://www.marthatrotts.ca/wp-content/plugins/formcraft/file-upload/server/content/files/1608e71f2c383b---36598228981.pdf
    • https://www.rogierstoel.nl/wp-content/plugins/super-forms/uploads/php/files/h75mubcegga541jhnfoooh5t0s/70920938895.pdf
    • https://protechlighting.com/wp-content/plugins/super-forms/uploads/php/files/103051412831c5db657b52869dec76fa/14439370337.pdf
    • https://amesmedicalservices.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bdb64f99ed7---simirulepidiwugi.pdf
    • http://sungsam.net/userData/board/file/mibozubenin.pdf
    • https://newat.ru/wp-content/plugins/super-forms/uploads/php/files/b7e1ee5fccd5468fde87f992b1d63533/95291253283.pdf
    • https://brokenspoke.com/wp-content/plugins/super-forms/uploads/php/files/c677db393abb53814ae43eb2fd7a7e41/divezatipo.pdf
    • http://www.siscard.com/wp-content/plugins/formcraft/file-upload/server/content/files/160e84d7427950---36429853393.pdf
    • https://directprocessors.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a6a58e2bbe0---17694220963.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/FevRqgeaUVY/uplcv?utm_term=free+christmas+labels+to+print
    • 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_off0000d5b4.bin
3f2d30dfe4b3c5eedd7d10e42dfc52f224c33ed52ab880132eed04684b090f83
pdf-font-stream PDF embedded font (sfnt) at offset 0xD5B4 17084 bytes
font_01_sfnt_off0001027c.bin
75ca3ca6932d1e3720b60c051b99824418bee8b7a25f90debd18ea80d06768e8
pdf-font-stream PDF embedded font (sfnt) at offset 0x1027C 10756 bytes
font_02_sfnt_off00011aca.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x11ACA 16792 bytes