Malicious PDF — malware analysis report

Static analysis result for SHA-256 a89bd12b21ef125f…

MALICIOUS

PDF

50.0 KB Created: 2020-08-31 16:33:11 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: db9e8f51758f38d78daef0d95d8dd5a3 SHA-1: 46d4fa848ccc4fcf84e08c7a2a62a7391fd814f0 SHA-256: a89bd12b21ef125fc0b3f4c57b46f4bf9bd70b7e7f6911f7106afeb16ded211b
152 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1059.001 PowerShell

The PDF contains a link to a known malicious redirector, ttraff.com, which is presented as interview preparation material. The PDF also contains a large number of links to other PDFs hosted on static.usrfiles.com, suggesting a link farm or SEO poisoning tactic. The ML classifier strongly indicated maliciousness, and the presence of a malicious redirector URL confirms the malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 4

  • PDF links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK
    PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • 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://ttraff.com/wix?keyword=competency+based+interview+answers+flexibility
    • https://static.usrfiles.com/ugd/3d0627_7f8296ee3d4f4599b3a658425e24f8b2.pdf
    • https://static.usrfiles.com/ugd/724fb5_b88d1863a2ae468a84c66b55d343d282.pdf
    • https://static.usrfiles.com/ugd/9e53d4_3409e0cb2cd64720b70df64054acfb97.pdf
    • https://static.usrfiles.com/ugd/90423f_0f634e96118c47b3bc1bba434fe27af0.pdf
    • https://static.usrfiles.com/ugd/b8c837_dd6b989234fb4b62b9efc3dbff31a08e.pdf
    • https://static.usrfiles.com/ugd/c1615c_e7d67452b0564098a116f7fc863a716e.pdf
    • https://cdn.shopify.com/s/files/1/0437/9970/7810/files/cute_august_2020_calendar.pdf
    • https://cdn.shopify.com/s/files/1/0431/3025/7568/files/safe_haven_book.pdf
    • https://cdn.shopify.com/s/files/1/0434/5180/9957/files/56243962695.pdf
    • https://cdn.shopify.com/s/files/1/0428/9835/8432/files/tipibag.pdf
    • https://static.usrfiles.com/ugd/c7ef1a_6a7c17a4e7b746e9a7f234819778eb97.pdf
    • https://static.usrfiles.com/ugd/067ecb_324870bcf68d4fb8bf4214f2e87d04c3.pdf
    • https://static.usrfiles.com/ugd/857e61_e40af8b2b929435ca287abdf37b803ff.pdf
    • https://static.usrfiles.com/ugd/5bb01c_548c1d345ade4977b149d79cb1fb10e8.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/

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00008592.bin
39ba01cf2c5ec69701537a4643b93f1ddad9611859bc5f09ef48cc81971b4ffd
pdf-font-stream PDF embedded font (sfnt) at offset 0x8592 5668 bytes
font_01_sfnt_off000098d5.bin
aedefc9189f67f2b50e2848d24398ddf678bd71612ad4808eb393d768e7ded08
pdf-font-stream PDF embedded font (sfnt) at offset 0x98D5 9856 bytes